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VB.NET || How To Add Simple Object Change Tracking To Track Changes Using VB.NET

April 23, 2022 admin No comments

The following is a module with functions which demonstrates how to add simple object change tracking to track changes made to an object using VB.NET.

Contents

1. Overview 2. Basic Usage 3. Accept Changes 4. Reject Changes 5. Ignore Tracking For Property 6. Notify Property Changed 7. Utils Namespace 8. More Examples

1. Overview

The following is a simple abstract change tracker class which implements INotifyPropertyChanged and IRevertibleChangeTracking which provides functionality to track object changes, and to ‘accept’ or ‘revert’ changes.

To use this class, simply inherit the abstract class, and your all set!

Note: Don’t forget to include the ‘Utils Namespace‘ before running the examples!

2. Basic Usage

The example below demonstrates the use of ChangeTracker.BeginChanges to start tracking object changes, as well as ChangeTracker.GetChanges to get the changes made to an object.

The following example demonstrates the basic usage of adding change tracking to an object, and making and getting changes.



		
		
			2. Basic Usage
			
Visual Basic .NET
			
			' Basic Usage

Imports Utils

' Declare class and inherit ChangeTracker
Public Class Person : Inherits ChangeTracker
    Public Property FirstName As String
    Public Property LastName As String
    Public Property Age As Integer?
End Class

' Declare data
Dim person = New Person With {
    .FirstName = "Kenneth",
    .LastName = "Perkins",
    .Age = 31
}

' Required: Changes made to this object will start being
' tracked the moment this function is called
person.BeginChanges()

' Make changes to the object
person.FirstName = "Jennifer"
person.LastName = "Nguyen"
person.Age = 28

' Get changes made to the object
Dim changes = person.GetChanges()

' Display the changes
Debug.Print($"Changes: {changes.Count}")
For Each change In changes
    Debug.Print($"    PropertyName: {change.PropertyName}, OriginalValue: {change.OriginalValue}, CurrentValue: {change.CurrentValue}")
Next

' expected output:
'    Changes: 3
'        PropertyName: FirstName, OriginalValue: Kenneth, CurrentValue: Jennifer
'        PropertyName: LastName, OriginalValue: Perkins, CurrentValue: Nguyen
'        PropertyName: Age, OriginalValue: 31, CurrentValue: 28
			
				
					
				
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						' Basic Usage
 
Imports Utils
 
' Declare class and inherit ChangeTracker
Public Class Person : Inherits ChangeTracker
    Public Property FirstName As String
    Public Property LastName As String
    Public Property Age As Integer?
End Class
 
' Declare data
Dim person = New Person With {
    .FirstName = "Kenneth",
    .LastName = "Perkins",
    .Age = 31
}
 
' Required: Changes made to this object will start being
' tracked the moment this function is called
person.BeginChanges()
 
' Make changes to the object
person.FirstName = "Jennifer"
person.LastName = "Nguyen"
person.Age = 28
 
' Get changes made to the object
Dim changes = person.GetChanges()
 
' Display the changes
Debug.Print($"Changes: {changes.Count}")
For Each change In changes
    Debug.Print($"    PropertyName: {change.PropertyName}, OriginalValue: {change.OriginalValue}, CurrentValue: {change.CurrentValue}")
Next
 
' expected output:
'    Changes: 3
'        PropertyName: FirstName, OriginalValue: Kenneth, CurrentValue: Jennifer
'        PropertyName: LastName, OriginalValue: Perkins, CurrentValue: Nguyen
'        PropertyName: Age, OriginalValue: 31, CurrentValue: 28

3. Accept Changes

The example below demonstrates the use of ChangeTracker.AcceptChanges to accept modification changes made to an object.

This function commits all the changes made to the object since either ChangeTracker.BeginChanges was called, or since ChangeTracker.AcceptChanges was last called.

When the accept function is called, all the changes made to the object up to that point will be marked as the current ‘source of truth’ for change tracking.



		
		
			3. Accept Changes
			
Visual Basic .NET
			
			' Accept Changes

Imports Utils

' Declare class and inherit ChangeTracker
Public Class Person : Inherits ChangeTracker
    Public Property FirstName As String
    Public Property LastName As String
    Public Property Age As Integer?
End Class

' Declare data
Dim person = New Person With {
    .FirstName = "Kenneth",
    .LastName = "Perkins",
    .Age = 31
}

' Required: Changes made to this object will start being
' tracked the moment this function is called
person.BeginChanges()

' Make changes to the object
person.FirstName = "Lynn"
person.LastName = "P"
person.Age = 10

' Accept all the changes made to the object up to
' this point as the source of truth for change tracking
person.AcceptChanges()

' Get changes made to the object
Dim changes = person.GetChanges()

' Display the changes
' Note: No changes will display because the most recent modifications has been accepted
Debug.Print($"Changes: {changes.Count}")
For Each change In changes
    Debug.Print($"    PropertyName: {change.PropertyName}, OriginalValue: {change.OriginalValue}, CurrentValue: {change.CurrentValue}")
Next

' expected output:
'    Changes: 0
			
				
					
				
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						' Accept Changes
 
Imports Utils
 
' Declare class and inherit ChangeTracker
Public Class Person : Inherits ChangeTracker
    Public Property FirstName As String
    Public Property LastName As String
    Public Property Age As Integer?
End Class
 
' Declare data
Dim person = New Person With {
    .FirstName = "Kenneth",
    .LastName = "Perkins",
    .Age = 31
}
 
' Required: Changes made to this object will start being
' tracked the moment this function is called
person.BeginChanges()
 
' Make changes to the object
person.FirstName = "Lynn"
person.LastName = "P"
person.Age = 10
 
' Accept all the changes made to the object up to
' this point as the source of truth for change tracking
person.AcceptChanges()
 
' Get changes made to the object
Dim changes = person.GetChanges()
 
' Display the changes
' Note: No changes will display because the most recent modifications has been accepted
Debug.Print($"Changes: {changes.Count}")
For Each change In changes
    Debug.Print($"    PropertyName: {change.PropertyName}, OriginalValue: {change.OriginalValue}, CurrentValue: {change.CurrentValue}")
Next
 
' expected output:
'    Changes: 0

4. Reject Changes

The example below demonstrates the use of ChangeTracker.RejectChanges to reject modification changes made to an object.

This function rejects all the changes made to the object since either ChangeTracker.BeginChanges was called, or since ChangeTracker.AcceptChanges was last called.

When the reject function is called, all the changes made to the object up to that point reverts back to the objects state before modifications initially began or modifications was last accepted.



		
		
			4. Reject Changes
			
Visual Basic .NET
			
			' Reject Changes

Imports Utils

' Declare class and inherit ChangeTracker
Public Class Person : Inherits ChangeTracker
    Public Property FirstName As String
    Public Property LastName As String
    Public Property Age As Integer?
End Class

' Declare data
Dim person = New Person With {
    .FirstName = "Kenneth",
    .LastName = "Perkins",
    .Age = 31
}

' Required: Changes made to this object will start being
' tracked the moment this function is called
person.BeginChanges()

' Make changes to the object
person.FirstName = "Sole"
person.LastName = "P"
person.Age = 19

' Rejects all the changes made to the object up to
' this point and reverts back to the objects state
' before modifications were made
person.RejectChanges()

' Get changes made to the object
Dim changes = person.GetChanges()

' Display the changes
' Note: No changes will display because the most recent modifications has been rejected
Debug.Print($"Changes: {changes.Count}")
For Each change In changes
    Debug.Print($"    PropertyName: {change.PropertyName}, OriginalValue: {change.OriginalValue}, CurrentValue: {change.CurrentValue}")
Next

' expected output:
'    Changes: 0
			
				
					
				
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						' Reject Changes
 
Imports Utils
 
' Declare class and inherit ChangeTracker
Public Class Person : Inherits ChangeTracker
    Public Property FirstName As String
    Public Property LastName As String
    Public Property Age As Integer?
End Class
 
' Declare data
Dim person = New Person With {
    .FirstName = "Kenneth",
    .LastName = "Perkins",
    .Age = 31
}
 
' Required: Changes made to this object will start being
' tracked the moment this function is called
person.BeginChanges()
 
' Make changes to the object
person.FirstName = "Sole"
person.LastName = "P"
person.Age = 19
 
' Rejects all the changes made to the object up to
' this point and reverts back to the objects state
' before modifications were made
person.RejectChanges()
 
' Get changes made to the object
Dim changes = person.GetChanges()
 
' Display the changes
' Note: No changes will display because the most recent modifications has been rejected
Debug.Print($"Changes: {changes.Count}")
For Each change In changes
    Debug.Print($"    PropertyName: {change.PropertyName}, OriginalValue: {change.OriginalValue}, CurrentValue: {change.CurrentValue}")
Next
 
' expected output:
'    Changes: 0

5. Ignore Tracking For Property

The example below demonstrates the use of ChangeTracker.ChangeTrackerIgnore attribute to mark a specific property to be ignored from change tracking.



		
		
			5. Ignore Tracking For Property
			
Visual Basic .NET
			
			' Ignore Tracking For Property

Imports Utils

' Declare class and inherit ChangeTracker
Public Class Person : Inherits ChangeTracker
    Public Property FirstName As String
    Public Property LastName As String
    <ChangeTrackerIgnore>
    Public Property Age As Integer?
End Class

' Declare data
Dim person = New Person With {
    .FirstName = "Kenneth",
    .LastName = "Perkins",
    .Age = 31
}

' Required: Changes made to this object will start being
' tracked the moment this function is called
person.BeginChanges()

' Make changes to the object
person.FirstName = "Jennifer"
person.LastName = "Nguyen"
person.Age = 28

' Get changes made to the object
Dim changes = person.GetChanges()

' Display the changes
Debug.Print($"Changes: {changes.Count}")
For Each change In changes
    Debug.Print($"    PropertyName: {change.PropertyName}, OriginalValue: {change.OriginalValue}, CurrentValue: {change.CurrentValue}")
Next

' expected output:
'    Changes: 2
'        PropertyName: FirstName, OriginalValue: Kenneth, CurrentValue: Jennifer
'        PropertyName: LastName, OriginalValue: Perkins, CurrentValue: Nguyen
			
				
					
				
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						' Ignore Tracking For Property
 
Imports Utils
 
' Declare class and inherit ChangeTracker
Public Class Person : Inherits ChangeTracker
    Public Property FirstName As String
    Public Property LastName As String
    <ChangeTrackerIgnore>
    Public Property Age As Integer?
End Class
 
' Declare data
Dim person = New Person With {
    .FirstName = "Kenneth",
    .LastName = "Perkins",
    .Age = 31
}
 
' Required: Changes made to this object will start being
' tracked the moment this function is called
person.BeginChanges()
 
' Make changes to the object
person.FirstName = "Jennifer"
person.LastName = "Nguyen"
person.Age = 28
 
' Get changes made to the object
Dim changes = person.GetChanges()
 
' Display the changes
Debug.Print($"Changes: {changes.Count}")
For Each change In changes
    Debug.Print($"    PropertyName: {change.PropertyName}, OriginalValue: {change.OriginalValue}, CurrentValue: {change.CurrentValue}")
Next
 
' expected output:
'    Changes: 2
'        PropertyName: FirstName, OriginalValue: Kenneth, CurrentValue: Jennifer
'        PropertyName: LastName, OriginalValue: Perkins, CurrentValue: Nguyen

6. Notify Property Changed

The example below demonstrates the use of ChangeTracker.NotifyPropertyChanged to fire the PropertyChanged event notifying that the specified property value has changed.

In the class declaration, simply add ChangeTracker.NotifyPropertyChanged to the properties you wish to notify changes, and add a PropertyChanged event handler function to receive the notifications.



		
		
			6. Notify Property Changed
			
Visual Basic .NET
			
			' Notify Property Changed

Imports Utils

' Declare class and inherit ChangeTracker
' Modify the properties you wish to notify changes
Public Class Person : Inherits ChangeTracker
    Private _firstName As String
    Public Property FirstName As String
        Get
            Return _firstName
        End Get
        Set(value As String)
            _firstName = value
            NotifyPropertyChanged(value)
        End Set
    End Property

    Private _lastName As String
    Public Property LastName As String
        Get
            Return _lastName
        End Get
        Set(value As String)
            _lastName = value
            NotifyPropertyChanged(value)
        End Set
    End Property

    Private _age As Integer?
    Public Property Age As Integer?
        Get
            Return _age
        End Get
        Set(value As Integer?)
            _age = value
            NotifyPropertyChanged(value)
        End Set
    End Property
End Class

' Declare data
Dim person = New Person With {
    .FirstName = "Kenneth",
    .LastName = "Perkins",
    .Age = 31
}

' Set custom event handler function for property changed event
AddHandler person.PropertyChanged, AddressOf Person_PropertyChanged

' Required: Changes made to this object will start being
' tracked the moment this function is called
person.BeginChanges()

' Make changes to the object
person.FirstName = "Jennifer"
person.LastName = "Nguyen"
person.Age = 28


' Declare Custom event handler function for the PropertyChanged event
Public Sub Person_PropertyChanged(sender As Object, e As System.ComponentModel.PropertyChangedEventArgs)
    Dim eventArgs = CType(e, ChangeTracker.PropertyChangedTrackedEventArgs)
    Debug.Print($"Event Handler Changes:")
    Debug.Print($"    PropertyName: {eventArgs.PropertyName}, OriginalValue: {eventArgs.OriginalValue}, CurrentValue: {eventArgs.CurrentValue}")
End Sub

' expected output:
'    Event Handler Changes:
'        PropertyName: FirstName, OriginalValue: Kenneth, CurrentValue: Jennifer
'    Event Handler Changes:
'        PropertyName: LastName, OriginalValue: Perkins, CurrentValue: Nguyen
'    Event Handler Changes:
'        PropertyName: Age, OriginalValue: 31, CurrentValue: 28
			
				
					
				
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						' Notify Property Changed
 
Imports Utils
 
' Declare class and inherit ChangeTracker
' Modify the properties you wish to notify changes
Public Class Person : Inherits ChangeTracker
    Private _firstName As String
    Public Property FirstName As String
        Get
            Return _firstName
        End Get
        Set(value As String)
            _firstName = value
            NotifyPropertyChanged(value)
        End Set
    End Property
 
    Private _lastName As String
    Public Property LastName As String
        Get
            Return _lastName
        End Get
        Set(value As String)
            _lastName = value
            NotifyPropertyChanged(value)
        End Set
    End Property
 
    Private _age As Integer?
    Public Property Age As Integer?
        Get
            Return _age
        End Get
        Set(value As Integer?)
            _age = value
            NotifyPropertyChanged(value)
        End Set
    End Property
End Class
 
' Declare data
Dim person = New Person With {
    .FirstName = "Kenneth",
    .LastName = "Perkins",
    .Age = 31
}
 
' Set custom event handler function for property changed event
AddHandler person.PropertyChanged, AddressOf Person_PropertyChanged
 
' Required: Changes made to this object will start being
' tracked the moment this function is called
person.BeginChanges()
 
' Make changes to the object
person.FirstName = "Jennifer"
person.LastName = "Nguyen"
person.Age = 28
 
 
' Declare Custom event handler function for the PropertyChanged event
Public Sub Person_PropertyChanged(sender As Object, e As System.ComponentModel.PropertyChangedEventArgs)
    Dim eventArgs = CType(e, ChangeTracker.PropertyChangedTrackedEventArgs)
    Debug.Print($"Event Handler Changes:")
    Debug.Print($"    PropertyName: {eventArgs.PropertyName}, OriginalValue: {eventArgs.OriginalValue}, CurrentValue: {eventArgs.CurrentValue}")
End Sub
 
' expected output:
'    Event Handler Changes:
'        PropertyName: FirstName, OriginalValue: Kenneth, CurrentValue: Jennifer
'    Event Handler Changes:
'        PropertyName: LastName, OriginalValue: Perkins, CurrentValue: Nguyen
'    Event Handler Changes:
'        PropertyName: Age, OriginalValue: 31, CurrentValue: 28

7. Utils Namespace

The following is the Utils Namespace. Include this in your project to start using!



		
		
			Utils Namespace
			
Visual Basic .NET
			
			' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Apr 23, 2022
'    Taken From: http://programmingnotes.org/
'    File:  Utils.cs
'    Description: Handles general utility functions
' ============================================================================
Option Strict On
Option Explicit On
Imports System
Imports System.Linq
Imports System.Reflection
Imports System.Collections.Generic
Imports System.Runtime.CompilerServices
Imports System.ComponentModel

Namespace Global.Utils
    Public MustInherit Class ChangeTracker : Implements System.ComponentModel.INotifyPropertyChanged, System.ComponentModel.IRevertibleChangeTracking
        Protected Property Tracked As Dictionary(Of String, ITrackedChange)
        Public Event PropertyChanged As System.ComponentModel.PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged
        Public ReadOnly Property IsTracking As Boolean
            Get
                Return Tracked.Count > 0
            End Get
        End Property

        ''' <summary>
        ''' Gets the objects changed status
        ''' </summary>
        ''' <returns><see langword="true"/> if the objects content has changed since either <see cref="BeginChanges"/>
        ''' was called, or since <see cref="AcceptChanges"/> was last called; <see langword="false"/> otherwise</returns>
        Public Property IsChanged As Boolean Implements IRevertibleChangeTracking.IsChanged
            Get
                If Not _isChanged AndAlso IsTracking Then
                    Dim trackedChanges = GetTrackedChanges()
                    If trackedChanges.Any(Function(x) x.DetectChange(GetValue(x.Property))) Then
                        _isChanged = True
                    End If
                End If
                Return _isChanged
            End Get
            Protected Set(value As Boolean)
                _isChanged = value
            End Set
        End Property
        Private _isChanged As Boolean = False

        Protected Sub New()
            Tracked = New Dictionary(Of String, ITrackedChange)()
        End Sub

        ''' <summary>
        ''' Fires the PropertyChanged event notifying that the specified property value changed
        ''' </summary>
        ''' <param name="currentValue">The current value</param>
        ''' <param name="originalValue">The original value</param>
        ''' <param name="propertyName">The corresponding property name</param>
        Protected Sub NotifyPropertyChanged(currentValue As Object, originalValue As Object,
                                            <CallerMemberName> Optional propertyName As String = "")
            RaiseEvent PropertyChanged(Me, New PropertyChangedTrackedEventArgs(propertyName, originalValue, currentValue))
        End Sub

        ''' <summary>
        ''' Fires the PropertyChanged event notifying that the specified property value changed
        ''' </summary>
        ''' <param name="currentValue">The current value</param>
        ''' <param name="propertyName">The corresponding property name</param>
        Protected Overridable Sub NotifyPropertyChanged(currentValue As Object,
                                                        <CallerMemberName> Optional propertyName As String = "")
            NotifyPropertyChanged(currentValue, GetTrackedChange(propertyName)?.OriginalValue, propertyName)
        End Sub

        ''' <summary>
        ''' Starts the tracking operation on the object. Changes made to the
        ''' object will start being tracked the moment this function is called
        ''' </summary>
        ''' <exception cref="InvalidOperationException">Changes have already begun</exception>
        Public Overridable Sub BeginChanges()
            ThrowIfTrackingStarted()
            Track(GetTrackableProperties())
            IsChanged = False
        End Sub

        ''' <summary>
        ''' Ends the tracking operation on the object. Any pending tracked changes made to the
        ''' object since either <see cref="BeginChanges"/> was called, or since <see cref="AcceptChanges"/>
        ''' was last called will be lost the moment this function is called
        ''' </summary>
        ''' <exception cref="InvalidOperationException">Change tracking has not started</exception>
        Public Overridable Sub EndChanges()
            ThrowIfTrackingNotStarted()
            Tracked.Clear()
            IsChanged = False
        End Sub

        ''' <summary>
        ''' Sets the current object state as its default state by accepting the modifications.
        ''' Commits all the changes made to this object since either <see cref="BeginChanges"/>
        ''' was called, or since <see cref="AcceptChanges"/> was last called
        ''' </summary>
        ''' <exception cref="InvalidOperationException">Change tracking has not started</exception>
        Public Overridable Sub AcceptChanges() Implements IChangeTracking.AcceptChanges
            ThrowIfTrackingNotStarted()
            Dim trackedChanges = UpdateTracked()
            For Each change In trackedChanges
                change.AcceptChange()
            Next
            IsChanged = False
        End Sub

        ''' <summary>
        ''' Resets the current objects state by rejecting the modifications. Rejects
        ''' all changes made to the object since either <see cref="BeginChanges"/>
        ''' was called, or since <see cref="AcceptChanges"/> was last called
        ''' </summary>
        ''' <exception cref="InvalidOperationException">Change tracking has not started</exception>
        Public Overridable Sub RejectChanges() Implements IRevertibleChangeTracking.RejectChanges
            ThrowIfTrackingNotStarted()
            Dim trackedChanges = GetTrackedChanges()
            For Each change In trackedChanges
                SetValue(change.[Property], change.OriginalValue)
                change.RejectChange()
            Next
            IsChanged = False
        End Sub

        ''' <summary>
        ''' Returns a list containing information of all the properties with changes
        ''' applied to it since either <see cref="BeginChanges"/> was called, or
        ''' since <see cref="AcceptChanges"/> was last called
        ''' </summary>
        ''' <returns>A list containing the changes made to the object</returns>
        ''' <exception cref="InvalidOperationException">Change tracking has not started</exception>
        Public Overridable Function GetChanges() As List(Of ITrackedChange)
            ThrowIfTrackingNotStarted()
            Dim result = New List(Of ITrackedChange)()
            Dim trackedChanges = UpdateTracked()
            For Each change In trackedChanges
                If change.HasChanges Then
                    result.Add(change)
                End If
            Next
            Return result
        End Function

        ''' <summary>
        ''' Returns a list containing information of all the properties being tracked
        ''' </summary>
        ''' <returns>A list containing property tracking information</returns>
        ''' <exception cref="InvalidOperationException">Change tracking has not started</exception>
        Public Function GetTracked() As List(Of ITrackedChange)
            ThrowIfTrackingNotStarted()
            Return Tracked.Values.ToList()
        End Function

        ''' <summary>
        ''' Updates the tracking status of all the properties being tracked
        ''' </summary>
        ''' <returns>A list containing properties being tracked</returns>
        Protected Function UpdateTracked() As IEnumerable(Of TrackedChange)
            Dim trackedChanges = GetTrackedChanges()
            Track(trackedChanges.Select(Function(x) x.Property))
            Return trackedChanges
        End Function

        ''' <summary>
        ''' Keeps track of the original and current values of the provided properties
        ''' </summary>
        ''' <param name="properties">The properties to track</param>
        Protected Sub Track(properties As IEnumerable(Of PropertyInfo))
            If properties IsNot Nothing Then
                For Each prop In properties
                    Track(prop, GetValue(prop))
                Next
            End If
        End Sub

        ''' <summary>
        ''' Keeps track of the original and current value of the provided property
        ''' </summary>
        ''' <param name="property">The property to track</param>
        ''' <param name="currentValue">The current value of the property</param>
        Protected Sub Track([property] As PropertyInfo, currentValue As Object)
            Dim currentChange As TrackedChange = Nothing
            If Not IsTrackedChange([property].Name) Then
                Dim hasChangedFunc As Func(Of Object, Object, Boolean) =
                    Function(original, current)
                        Return HasValuesChanged(original, current)
                    End Function
                currentChange = New TrackedChange With {
                    .Property = [property],
                    .OriginalValue = currentValue,
                    .HasChangedFunc = hasChangedFunc
                }
                Tracked.Add([property].Name, currentChange)
            Else
                currentChange = GetTrackedChange([property].Name)
                currentChange.CurrentValue = currentValue
                currentChange.Status = TrackedChange.TrackingStatus.Checked
                currentChange.LastChecked = Date.Now
            End If
            If currentChange.HasChanges Then
                IsChanged = True
            End If
        End Sub

        ''' <summary>
        ''' Class which contains property tracking information
        ''' </summary>
        Protected Class TrackedChange : Implements ITrackedChange
            Public Enum TrackingStatus
                Unchecked
                Checked
            End Enum
            Public Property [Property] As PropertyInfo
            Public ReadOnly Property PropertyName As String Implements ITrackedChange.PropertyName
                Get
                    Return [Property]?.Name
                End Get
            End Property
            Public Property OriginalValue As Object Implements ITrackedChange.OriginalValue
            Public Property CurrentValue As Object Implements ITrackedChange.CurrentValue
            Public Property Status As TrackingStatus = TrackingStatus.Unchecked
            Public ReadOnly Property HasChanges As Boolean
                Get
                    Return Status = TrackingStatus.Checked AndAlso DetectChange(CurrentValue)
                End Get
            End Property
            Public Property LastChecked As Date? = Nothing
            Public Property HasChangedFunc As Func(Of Object, Object, Boolean)
            Public Function DetectChange(currentValue As Object) As Boolean
                Return HasChangedFunc(OriginalValue, currentValue)
            End Function
            Public Sub AcceptChange()
                OriginalValue = CurrentValue
                RejectChange()
            End Sub
            Public Sub RejectChange()
                CurrentValue = Nothing
                Status = TrackingStatus.Unchecked
                LastChecked = Nothing
            End Sub
        End Class

        ''' <summary>
        ''' Provides support for object change tracking
        ''' </summary>
        Interface ITrackedChange
            ReadOnly Property PropertyName As String
            ReadOnly Property OriginalValue As Object
            ReadOnly Property CurrentValue As Object
        End Interface

        ''' <summary>
        ''' Provides data for the <see cref=" System.ComponentModel.PropertyChangedEventArgs"/> event
        ''' </summary>
        Public Class PropertyChangedTrackedEventArgs : Inherits System.ComponentModel.PropertyChangedEventArgs
            Public Property OriginalValue As Object
            Public Property CurrentValue As Object

            Public Sub New(propertyName As String, originalValue As Object, currentValue As Object)
                MyBase.New(propertyName)
                Me.OriginalValue = originalValue
                Me.CurrentValue = currentValue
            End Sub
        End Class

        ''' <summary>
        ''' Attribute which allows a property to be ignored from being tracked
        ''' </summary>
        Public Class ChangeTrackerIgnoreAttribute : Inherits System.Attribute
        End Class

#Region "Helpers"
        Protected Function IsTrackedChange(propertyName As String) As Boolean
            Return Tracked.ContainsKey(propertyName)
        End Function
        Protected Function GetTrackedChange(propertyName As String) As TrackedChange
            Return If(IsTrackedChange(propertyName), CType(Tracked(propertyName), TrackedChange), Nothing)
        End Function
        Protected Function GetTrackedChanges() As IEnumerable(Of TrackedChange)
            Return Tracked.Select(Function(pair) CType(pair.Value, TrackedChange))
        End Function
        Protected Overridable Function GetTrackableProperties() As IEnumerable(Of PropertyInfo)
            Return Me.GetType().GetProperties() _
                .Where(Function(p)
                           Return Not p.DeclaringType.Equals(GetType(ChangeTracker)) _
                           AndAlso p.CanRead _
                           AndAlso p.CanWrite _
                           AndAlso Not p.GetCustomAttributes(Of ChangeTrackerIgnoreAttribute)(False).Any()
                       End Function)
        End Function
        Protected Overridable Function GetValue([property] As PropertyInfo) As Object
            Return [property]?.GetValue(Me, If([property].GetIndexParameters().Count() = 1, New Object() {Nothing}, Nothing))
        End Function
        Protected Overridable Sub SetValue([property] As PropertyInfo, value As Object)
            If [property] IsNot Nothing AndAlso [property].CanWrite Then
                [property].SetValue(Me, value)
            End If
        End Sub
        Protected Overridable Function HasValuesChanged(Of T)(originalValue As T, currentValue As T) As Boolean
            Return Not EqualityComparer(Of T).Default.Equals(originalValue, currentValue)
        End Function
        Protected Sub ThrowIfTrackingNotStarted()
            If Not IsTracking Then
                Throw New InvalidOperationException("Change tracking has not started. Call 'BeginChanges' to start change tracking")
            End If
        End Sub
        Protected Sub ThrowIfTrackingStarted()
            If IsTracking Then
                Throw New InvalidOperationException("Change tracking has already started")
            End If
        End Sub
#End Region
    End Class
End Namespace ' http://programmingnotes.org/
			
				
					
				
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						' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Apr 23, 2022
'    Taken From: http://programmingnotes.org/
'    File:  Utils.cs
'    Description: Handles general utility functions
' ============================================================================
Option Strict On
Option Explicit On
Imports System
Imports System.Linq
Imports System.Reflection
Imports System.Collections.Generic
Imports System.Runtime.CompilerServices
Imports System.ComponentModel
 
Namespace Global.Utils
    Public MustInherit Class ChangeTracker : Implements System.ComponentModel.INotifyPropertyChanged, System.ComponentModel.IRevertibleChangeTracking
        Protected Property Tracked As Dictionary(Of String, ITrackedChange)
        Public Event PropertyChanged As System.ComponentModel.PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged
        Public ReadOnly Property IsTracking As Boolean
            Get
                Return Tracked.Count > 0
            End Get
        End Property
 
        ''' <summary>
        ''' Gets the objects changed status
        ''' </summary>
        ''' <returns><see langword="true"/> if the objects content has changed since either <see cref="BeginChanges"/>
        ''' was called, or since <see cref="AcceptChanges"/> was last called; <see langword="false"/> otherwise</returns>
        Public Property IsChanged As Boolean Implements IRevertibleChangeTracking.IsChanged
            Get
                If Not _isChanged AndAlso IsTracking Then
                    Dim trackedChanges = GetTrackedChanges()
                    If trackedChanges.Any(Function(x) x.DetectChange(GetValue(x.Property))) Then
                        _isChanged = True
                    End If
                End If
                Return _isChanged
            End Get
            Protected Set(value As Boolean)
                _isChanged = value
            End Set
        End Property
        Private _isChanged As Boolean = False
 
        Protected Sub New()
            Tracked = New Dictionary(Of String, ITrackedChange)()
        End Sub
 
        ''' <summary>
        ''' Fires the PropertyChanged event notifying that the specified property value changed
        ''' </summary>
        ''' <param name="currentValue">The current value</param>
        ''' <param name="originalValue">The original value</param>
        ''' <param name="propertyName">The corresponding property name</param>
        Protected Sub NotifyPropertyChanged(currentValue As Object, originalValue As Object,
                                            <CallerMemberName> Optional propertyName As String = "")
            RaiseEvent PropertyChanged(Me, New PropertyChangedTrackedEventArgs(propertyName, originalValue, currentValue))
        End Sub
 
        ''' <summary>
        ''' Fires the PropertyChanged event notifying that the specified property value changed
        ''' </summary>
        ''' <param name="currentValue">The current value</param>
        ''' <param name="propertyName">The corresponding property name</param>
        Protected Overridable Sub NotifyPropertyChanged(currentValue As Object,
                                                        <CallerMemberName> Optional propertyName As String = "")
            NotifyPropertyChanged(currentValue, GetTrackedChange(propertyName)?.OriginalValue, propertyName)
        End Sub
 
        ''' <summary>
        ''' Starts the tracking operation on the object. Changes made to the
        ''' object will start being tracked the moment this function is called
        ''' </summary>
        ''' <exception cref="InvalidOperationException">Changes have already begun</exception>
        Public Overridable Sub BeginChanges()
            ThrowIfTrackingStarted()
            Track(GetTrackableProperties())
            IsChanged = False
        End Sub
 
        ''' <summary>
        ''' Ends the tracking operation on the object. Any pending tracked changes made to the
        ''' object since either <see cref="BeginChanges"/> was called, or since <see cref="AcceptChanges"/>
        ''' was last called will be lost the moment this function is called
        ''' </summary>
        ''' <exception cref="InvalidOperationException">Change tracking has not started</exception>
        Public Overridable Sub EndChanges()
            ThrowIfTrackingNotStarted()
            Tracked.Clear()
            IsChanged = False
        End Sub
 
        ''' <summary>
        ''' Sets the current object state as its default state by accepting the modifications.
        ''' Commits all the changes made to this object since either <see cref="BeginChanges"/>
        ''' was called, or since <see cref="AcceptChanges"/> was last called
        ''' </summary>
        ''' <exception cref="InvalidOperationException">Change tracking has not started</exception>
        Public Overridable Sub AcceptChanges() Implements IChangeTracking.AcceptChanges
            ThrowIfTrackingNotStarted()
            Dim trackedChanges = UpdateTracked()
            For Each change In trackedChanges
                change.AcceptChange()
            Next
            IsChanged = False
        End Sub
 
        ''' <summary>
        ''' Resets the current objects state by rejecting the modifications. Rejects
        ''' all changes made to the object since either <see cref="BeginChanges"/>
        ''' was called, or since <see cref="AcceptChanges"/> was last called
        ''' </summary>
        ''' <exception cref="InvalidOperationException">Change tracking has not started</exception>
        Public Overridable Sub RejectChanges() Implements IRevertibleChangeTracking.RejectChanges
            ThrowIfTrackingNotStarted()
            Dim trackedChanges = GetTrackedChanges()
            For Each change In trackedChanges
                SetValue(change.[Property], change.OriginalValue)
                change.RejectChange()
            Next
            IsChanged = False
        End Sub
 
        ''' <summary>
        ''' Returns a list containing information of all the properties with changes
        ''' applied to it since either <see cref="BeginChanges"/> was called, or
        ''' since <see cref="AcceptChanges"/> was last called
        ''' </summary>
        ''' <returns>A list containing the changes made to the object</returns>
        ''' <exception cref="InvalidOperationException">Change tracking has not started</exception>
        Public Overridable Function GetChanges() As List(Of ITrackedChange)
            ThrowIfTrackingNotStarted()
            Dim result = New List(Of ITrackedChange)()
            Dim trackedChanges = UpdateTracked()
            For Each change In trackedChanges
                If change.HasChanges Then
                    result.Add(change)
                End If
            Next
            Return result
        End Function
 
        ''' <summary>
        ''' Returns a list containing information of all the properties being tracked
        ''' </summary>
        ''' <returns>A list containing property tracking information</returns>
        ''' <exception cref="InvalidOperationException">Change tracking has not started</exception>
        Public Function GetTracked() As List(Of ITrackedChange)
            ThrowIfTrackingNotStarted()
            Return Tracked.Values.ToList()
        End Function
 
        ''' <summary>
        ''' Updates the tracking status of all the properties being tracked
        ''' </summary>
        ''' <returns>A list containing properties being tracked</returns>
        Protected Function UpdateTracked() As IEnumerable(Of TrackedChange)
            Dim trackedChanges = GetTrackedChanges()
            Track(trackedChanges.Select(Function(x) x.Property))
            Return trackedChanges
        End Function
 
        ''' <summary>
        ''' Keeps track of the original and current values of the provided properties
        ''' </summary>
        ''' <param name="properties">The properties to track</param>
        Protected Sub Track(properties As IEnumerable(Of PropertyInfo))
            If properties IsNot Nothing Then
                For Each prop In properties
                    Track(prop, GetValue(prop))
                Next
            End If
        End Sub
 
        ''' <summary>
        ''' Keeps track of the original and current value of the provided property
        ''' </summary>
        ''' <param name="property">The property to track</param>
        ''' <param name="currentValue">The current value of the property</param>
        Protected Sub Track([property] As PropertyInfo, currentValue As Object)
            Dim currentChange As TrackedChange = Nothing
            If Not IsTrackedChange([property].Name) Then
                Dim hasChangedFunc As Func(Of Object, Object, Boolean) =
                    Function(original, current)
                        Return HasValuesChanged(original, current)
                    End Function
                currentChange = New TrackedChange With {
                    .Property = [property],
                    .OriginalValue = currentValue,
                    .HasChangedFunc = hasChangedFunc
                }
                Tracked.Add([property].Name, currentChange)
            Else
                currentChange = GetTrackedChange([property].Name)
                currentChange.CurrentValue = currentValue
                currentChange.Status = TrackedChange.TrackingStatus.Checked
                currentChange.LastChecked = Date.Now
            End If
            If currentChange.HasChanges Then
                IsChanged = True
            End If
        End Sub
 
        ''' <summary>
        ''' Class which contains property tracking information
        ''' </summary>
        Protected Class TrackedChange : Implements ITrackedChange
            Public Enum TrackingStatus
                Unchecked
                Checked
            End Enum
            Public Property [Property] As PropertyInfo
            Public ReadOnly Property PropertyName As String Implements ITrackedChange.PropertyName
                Get
                    Return [Property]?.Name
                End Get
            End Property
            Public Property OriginalValue As Object Implements ITrackedChange.OriginalValue
            Public Property CurrentValue As Object Implements ITrackedChange.CurrentValue
            Public Property Status As TrackingStatus = TrackingStatus.Unchecked
            Public ReadOnly Property HasChanges As Boolean
                Get
                    Return Status = TrackingStatus.Checked AndAlso DetectChange(CurrentValue)
                End Get
            End Property
            Public Property LastChecked As Date? = Nothing
            Public Property HasChangedFunc As Func(Of Object, Object, Boolean)
            Public Function DetectChange(currentValue As Object) As Boolean
                Return HasChangedFunc(OriginalValue, currentValue)
            End Function
            Public Sub AcceptChange()
                OriginalValue = CurrentValue
                RejectChange()
            End Sub
            Public Sub RejectChange()
                CurrentValue = Nothing
                Status = TrackingStatus.Unchecked
                LastChecked = Nothing
            End Sub
        End Class
 
        ''' <summary>
        ''' Provides support for object change tracking
        ''' </summary>
        Interface ITrackedChange
            ReadOnly Property PropertyName As String
            ReadOnly Property OriginalValue As Object
            ReadOnly Property CurrentValue As Object
        End Interface
 
        ''' <summary>
        ''' Provides data for the <see cref=" System.ComponentModel.PropertyChangedEventArgs"/> event
        ''' </summary>
        Public Class PropertyChangedTrackedEventArgs : Inherits System.ComponentModel.PropertyChangedEventArgs
            Public Property OriginalValue As Object
            Public Property CurrentValue As Object
 
            Public Sub New(propertyName As String, originalValue As Object, currentValue As Object)
                MyBase.New(propertyName)
                Me.OriginalValue = originalValue
                Me.CurrentValue = currentValue
            End Sub
        End Class
 
        ''' <summary>
        ''' Attribute which allows a property to be ignored from being tracked
        ''' </summary>
        Public Class ChangeTrackerIgnoreAttribute : Inherits System.Attribute
        End Class
 
#Region "Helpers"
        Protected Function IsTrackedChange(propertyName As String) As Boolean
            Return Tracked.ContainsKey(propertyName)
        End Function
        Protected Function GetTrackedChange(propertyName As String) As TrackedChange
            Return If(IsTrackedChange(propertyName), CType(Tracked(propertyName), TrackedChange), Nothing)
        End Function
        Protected Function GetTrackedChanges() As IEnumerable(Of TrackedChange)
            Return Tracked.Select(Function(pair) CType(pair.Value, TrackedChange))
        End Function
        Protected Overridable Function GetTrackableProperties() As IEnumerable(Of PropertyInfo)
            Return Me.GetType().GetProperties() _
                .Where(Function(p)
                           Return Not p.DeclaringType.Equals(GetType(ChangeTracker)) _
                           AndAlso p.CanRead _
                           AndAlso p.CanWrite _
                           AndAlso Not p.GetCustomAttributes(Of ChangeTrackerIgnoreAttribute)(False).Any()
                       End Function)
        End Function
        Protected Overridable Function GetValue([property] As PropertyInfo) As Object
            Return [property]?.GetValue(Me, If([property].GetIndexParameters().Count() = 1, New Object() {Nothing}, Nothing))
        End Function
        Protected Overridable Sub SetValue([property] As PropertyInfo, value As Object)
            If [property] IsNot Nothing AndAlso [property].CanWrite Then
                [property].SetValue(Me, value)
            End If
        End Sub
        Protected Overridable Function HasValuesChanged(Of T)(originalValue As T, currentValue As T) As Boolean
            Return Not EqualityComparer(Of T).Default.Equals(originalValue, currentValue)
        End Function
        Protected Sub ThrowIfTrackingNotStarted()
            If Not IsTracking Then
                Throw New InvalidOperationException("Change tracking has not started. Call 'BeginChanges' to start change tracking")
            End If
        End Sub
        Protected Sub ThrowIfTrackingStarted()
            If IsTracking Then
                Throw New InvalidOperationException("Change tracking has already started")
            End If
        End Sub
#End Region
    End Class
End Namespace ' http://programmingnotes.org/

8. More Examples

Below are more examples demonstrating the use of the ‘Utils‘ Namespace. Don’t forget to include the module when running the examples!



		
		
			More Examples
			
Visual Basic .NET
			
			' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Apr 23, 2022
'    Taken From: http://programmingnotes.org/
'    File: Program.vb
'    Description: The following demonstrates the use of the Utils Namespace
' ============================================================================
Option Strict On
Option Explicit On
Imports System
Imports Utils

Public Module Program
    ' Declare class and inherit ChangeTracker
    ' Modify the properties you wish to notify changes
    Public Class Person : Inherits ChangeTracker
        Private _firstName As String
        Public Property FirstName As String
            Get
                Return _firstName
            End Get
            Set(value As String)
                _firstName = value
                NotifyPropertyChanged(value)
            End Set
        End Property

        Private _lastName As String
        Public Property LastName As String
            Get
                Return _lastName
            End Get
            Set(value As String)
                _lastName = value
                NotifyPropertyChanged(value)
            End Set
        End Property

        Private _age As Integer?
        '<ChangeTrackerIgnore>
        Public Property Age As Integer?
            Get
                Return _age
            End Get
            Set(value As Integer?)
                _age = value
                NotifyPropertyChanged(value)
            End Set
        End Property
    End Class

    Sub Main(args As String())
        Try
            ' Declare data
            Dim person = New Person With {
                .FirstName = "Kenneth",
                .LastName = "Perkins",
                .Age = 31
            }

            ' Set custom event handler function for property changed event
            AddHandler person.PropertyChanged, AddressOf Person_PropertyChanged

            ' Required: Changes made to this object will start being
            ' tracked the moment this function is called
            person.BeginChanges()

            Dim changes1 = person.GetChanges()

            ' Make changes to the object
            person.FirstName = "Jennifer"
            person.LastName = "Nguyen"
            person.Age = 28

            ' Get changes made to the object
            Dim changes2 = person.GetChanges()

            ' Display the changes
            DisplayChanges(changes2)

            ' --- Accept changes ---

            ' Make changes to the object
            person.FirstName = "Lynn"
            person.LastName = "P"
            person.Age = 10

            Dim changes3 = person.GetChanges()

            ' Accept all the changes made to the object up to
            ' this point as the source of truth for change tracking
            person.AcceptChanges()

            'Get changes made to the object
            Dim changes4 = person.GetChanges()

            ' Display the changes
            ' Note: No changes will display because the most recent modifications has been accepted
            DisplayChanges(changes4)

            ' --- Reject changes ---

            ' Make changes to the object
            person.FirstName = "Sole"
            person.LastName = "P"
            person.Age = 19

            ' Rejects all the changes made to the object up to
            ' this point and reverts back to the objects state
            ' before modifications were made
            person.RejectChanges()

            ' Get changes made to the object
            Dim changes5 = person.GetChanges()

            ' Display the changes
            ' Note: No changes will display because the most recent modifications has been rejected
            DisplayChanges(changes5)
        Catch ex As Exception
            Display(ex.ToString)
        Finally
            Console.ReadLine()
        End Try
    End Sub

    ' Declare Custom event handler function for the PropertyChanged event
    Public Sub Person_PropertyChanged(sender As Object, e As System.ComponentModel.PropertyChangedEventArgs)
        Dim eventArgs = CType(e, ChangeTracker.PropertyChangedTrackedEventArgs)
        Display($"Event Handler Changes:")
        Display($"    PropertyName: {eventArgs.PropertyName}, OriginalValue: {eventArgs.OriginalValue}, CurrentValue: {eventArgs.CurrentValue}")
    End Sub

    Public Sub DisplayChanges(changes As List(Of ChangeTracker.ITrackedChange))
        Display($"Changes: {changes.Count}")
        For Each change In changes
            Display($"    PropertyName: {change.PropertyName}, OriginalValue: {change.OriginalValue}, CurrentValue: {change.CurrentValue}")
        Next
        Display("============")
    End Sub

    Public Sub Display(message As String)
        Console.WriteLine(message)
        Debug.Print(message)
    End Sub
End Module ' http://programmingnotes.org/
			
				
					
				
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						' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Apr 23, 2022
'    Taken From: http://programmingnotes.org/
'    File: Program.vb
'    Description: The following demonstrates the use of the Utils Namespace
' ============================================================================
Option Strict On
Option Explicit On
Imports System
Imports Utils
 
Public Module Program
    ' Declare class and inherit ChangeTracker
    ' Modify the properties you wish to notify changes
    Public Class Person : Inherits ChangeTracker
        Private _firstName As String
        Public Property FirstName As String
            Get
                Return _firstName
            End Get
            Set(value As String)
                _firstName = value
                NotifyPropertyChanged(value)
            End Set
        End Property
 
        Private _lastName As String
        Public Property LastName As String
            Get
                Return _lastName
            End Get
            Set(value As String)
                _lastName = value
                NotifyPropertyChanged(value)
            End Set
        End Property
 
        Private _age As Integer?
        '<ChangeTrackerIgnore>
        Public Property Age As Integer?
            Get
                Return _age
            End Get
            Set(value As Integer?)
                _age = value
                NotifyPropertyChanged(value)
            End Set
        End Property
    End Class
 
    Sub Main(args As String())
        Try
            ' Declare data
            Dim person = New Person With {
                .FirstName = "Kenneth",
                .LastName = "Perkins",
                .Age = 31
            }
 
            ' Set custom event handler function for property changed event
            AddHandler person.PropertyChanged, AddressOf Person_PropertyChanged
 
            ' Required: Changes made to this object will start being
            ' tracked the moment this function is called
            person.BeginChanges()
 
            Dim changes1 = person.GetChanges()
 
            ' Make changes to the object
            person.FirstName = "Jennifer"
            person.LastName = "Nguyen"
            person.Age = 28
 
            ' Get changes made to the object
            Dim changes2 = person.GetChanges()
 
            ' Display the changes
            DisplayChanges(changes2)
 
            ' --- Accept changes ---
 
            ' Make changes to the object
            person.FirstName = "Lynn"
            person.LastName = "P"
            person.Age = 10
 
            Dim changes3 = person.GetChanges()
 
            ' Accept all the changes made to the object up to
            ' this point as the source of truth for change tracking
            person.AcceptChanges()
 
            'Get changes made to the object
            Dim changes4 = person.GetChanges()
 
            ' Display the changes
            ' Note: No changes will display because the most recent modifications has been accepted
            DisplayChanges(changes4)
 
            ' --- Reject changes ---
 
            ' Make changes to the object
            person.FirstName = "Sole"
            person.LastName = "P"
            person.Age = 19
 
            ' Rejects all the changes made to the object up to
            ' this point and reverts back to the objects state
            ' before modifications were made
            person.RejectChanges()
 
            ' Get changes made to the object
            Dim changes5 = person.GetChanges()
 
            ' Display the changes
            ' Note: No changes will display because the most recent modifications has been rejected
            DisplayChanges(changes5)
        Catch ex As Exception
            Display(ex.ToString)
        Finally
            Console.ReadLine()
        End Try
    End Sub
 
    ' Declare Custom event handler function for the PropertyChanged event
    Public Sub Person_PropertyChanged(sender As Object, e As System.ComponentModel.PropertyChangedEventArgs)
        Dim eventArgs = CType(e, ChangeTracker.PropertyChangedTrackedEventArgs)
        Display($"Event Handler Changes:")
        Display($"    PropertyName: {eventArgs.PropertyName}, OriginalValue: {eventArgs.OriginalValue}, CurrentValue: {eventArgs.CurrentValue}")
    End Sub
 
    Public Sub DisplayChanges(changes As List(Of ChangeTracker.ITrackedChange))
        Display($"Changes: {changes.Count}")
        For Each change In changes
            Display($"    PropertyName: {change.PropertyName}, OriginalValue: {change.OriginalValue}, CurrentValue: {change.CurrentValue}")
        Next
        Display("============")
    End Sub
 
    Public Sub Display(message As String)
        Console.WriteLine(message)
        Debug.Print(message)
    End Sub
End Module ' http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

VB.NET || How To Pad Center & Center Align A String Of Fixed Length Using VB.NET

July 18, 2021 admin No comments

The following is a module with functions which demonstrates how to pad center and center align a string of a fixed length using VB.NET.

The function demonstrated on this page center aligns the characters in a string by padding them on the left and right with a specified character, of a specified total length.

The returned string is padded with as many padding characters needed to reach a length of the specified total width.

The padding character is user defined, but if no padding character is specified, the string is padded using a whitespace (‘ ‘).

1. Pad Center

The example below demonstrates the use of ‘Utils.PadCenter‘ to center align a string of a fixed length.

In this example, the default padding character is used to pad the string, which is a whitespace (‘ ‘).



		
		
			1. Pad Center
			
Visual Basic .NET
			
			' Pad Center

Imports Utils

' Declare string
Dim original As String = "<-Kenneth->"

' Get padding width
Dim width As Integer = 15

' Display result
Debug.Print("Original:   '" & original & "'")
Debug.Print("Pad Center: '" & original.PadCenter(width) & "'")
Debug.Print("Pad Right:  '" & original.PadRight(width) & "'")
Debug.Print("Pad Left:   '" & original.PadLeft(width) & "'")

' expected output:
'    Original:   '<-Kenneth->'
'    Pad Center: '  <-Kenneth->  '
'    Pad Right:  '<-Kenneth->    '
'    Pad Left:   '    <-Kenneth->'
			
				
					
				
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						' Pad Center
 
Imports Utils
 
' Declare string
Dim original As String = "<-Kenneth->"
 
' Get padding width
Dim width As Integer = 15
 
' Display result
Debug.Print("Original:   '" & original & "'")
Debug.Print("Pad Center: '" & original.PadCenter(width) & "'")
Debug.Print("Pad Right:  '" & original.PadRight(width) & "'")
Debug.Print("Pad Left:   '" & original.PadLeft(width) & "'")
 
' expected output:
'    Original:   '<-Kenneth->'
'    Pad Center: '  <-Kenneth->  '
'    Pad Right:  '<-Kenneth->    '
'    Pad Left:   '    <-Kenneth->'

2. Utils Namespace

The following is the Utils Namespace. Include this in your project to start using!



		
		
			Utils Namespace
			
Visual Basic .NET
			
			' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Jul 18, 2021
'    Taken From: http://programmingnotes.org/
'    File: Utils.vb
'    Description: Handles general utility functions
' ============================================================================
Option Strict On
Option Explicit On

Namespace Global.Utils
    Public Module modUtils
        ''' <summary>
        ''' Returns a new string that center aligns the characters in a 
        ''' string by padding them on the left and right with a specified 
        ''' character, of a specified total length
        ''' </summary>
        ''' <param name="source">The source string</param>
        ''' <param name="totalWidth">The number of characters to pad the source string</param>
        ''' <param name="paddingChar">The padding character</param>
        ''' <returns>The modified source string padded with as many paddingChar
        ''' characters needed to create a length of totalWidth</returns>
        <Runtime.CompilerServices.Extension()>
        Public Function PadCenter(source As String, totalWidth As Integer, Optional paddingChar As Char = " "c) As String
            Dim spaces = totalWidth - source.Length
            Dim padLeft = CInt(spaces / 2 + source.Length)
            Return source.PadLeft(padLeft, paddingChar).PadRight(totalWidth, paddingChar)
        End Function
    End Module
End Namespace ' http://programmingnotes.org/
			
				
					
				
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						' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Jul 18, 2021
'    Taken From: http://programmingnotes.org/
'    File: Utils.vb
'    Description: Handles general utility functions
' ============================================================================
Option Strict On
Option Explicit On
 
Namespace Global.Utils
    Public Module modUtils
        ''' <summary>
        ''' Returns a new string that center aligns the characters in a 
        ''' string by padding them on the left and right with a specified 
        ''' character, of a specified total length
        ''' </summary>
        ''' <param name="source">The source string</param>
        ''' <param name="totalWidth">The number of characters to pad the source string</param>
        ''' <param name="paddingChar">The padding character</param>
        ''' <returns>The modified source string padded with as many paddingChar
        ''' characters needed to create a length of totalWidth</returns>
        <Runtime.CompilerServices.Extension()>
        Public Function PadCenter(source As String, totalWidth As Integer, Optional paddingChar As Char = " "c) As String
            Dim spaces = totalWidth - source.Length
            Dim padLeft = CInt(spaces / 2 + source.Length)
            Return source.PadLeft(padLeft, paddingChar).PadRight(totalWidth, paddingChar)
        End Function
    End Module
End Namespace ' http://programmingnotes.org/

3. More Examples

Below are more examples demonstrating the use of the ‘Utils‘ Namespace. Don’t forget to include the module when running the examples!



		
		
			More Examples
			
Visual Basic .NET
			
			' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Jul 18, 2021
'    Taken From: http://programmingnotes.org/
'    File: Program.vb
'    Description: The following demonstrates the use of the Utils Namespace
' ============================================================================
Option Strict On
Option Explicit On
Imports System
Imports Utils

Public Module Program
    Sub Main(args As String())
        Try
            ' Declare string
            Dim original As String = "<-Kenneth->"

            ' Get padding width
            Dim width As Integer = 15

            ' Display result
            Display("Original:   '" & original & "'")
            Display("Pad Center: '" & original.PadCenter(width) & "'")
            Display("Pad Right:  '" & original.PadRight(width) & "'")
            Display("Pad Left:   '" & original.PadLeft(width) & "'")
        Catch ex As Exception
            Display(ex.ToString)
        Finally
            Console.ReadLine()
        End Try
    End Sub

    Public Sub Display(message As String)
        Console.WriteLine(message)
        Debug.Print(message)
    End Sub
End Module ' http://programmingnotes.org/
			
				
					
				
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						' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Jul 18, 2021
'    Taken From: http://programmingnotes.org/
'    File: Program.vb
'    Description: The following demonstrates the use of the Utils Namespace
' ============================================================================
Option Strict On
Option Explicit On
Imports System
Imports Utils
 
Public Module Program
    Sub Main(args As String())
        Try
            ' Declare string
            Dim original As String = "<-Kenneth->"
 
            ' Get padding width
            Dim width As Integer = 15
 
            ' Display result
            Display("Original:   '" & original & "'")
            Display("Pad Center: '" & original.PadCenter(width) & "'")
            Display("Pad Right:  '" & original.PadRight(width) & "'")
            Display("Pad Left:   '" & original.PadLeft(width) & "'")
        Catch ex As Exception
            Display(ex.ToString)
        Finally
            Console.ReadLine()
        End Try
    End Sub
 
    Public Sub Display(message As String)
        Console.WriteLine(message)
        Debug.Print(message)
    End Sub
End Module ' http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

VB.NET || How To Create Multiple Tasks With Maximum Concurrency Using VB.NET

December 04, 2020 admin No comments

The following is a module with functions which demonstrates how to create multiple tasks with maximum concurrency using VB.NET.

The examples demonstrated on this page uses System.Threading.Tasks.Task to start and run tasks. They also use System.Threading.SemaphoreSlim to limit the number of tasks that can run concurrently.

The examples on this page demonstrates how to start and run multiple tasks with a maximum concurrency. It also demonstrates how to start and run multiple tasks with a return value.

1. Task – Maximum Concurrency

The example below demonstrates how to start and run multiple tasks with a maximum concurrency. For example purposes, the tasks do not return a value.

The functions shown in the example below are called asynchronously, but they can also be called synchronously.



		
		
			1. Task - Maximum Concurrency
			
Visual Basic .NET
			
			' Task - Maximum Concurrency

Dim concurrentTasks = 5
Dim semaphore = New System.Threading.SemaphoreSlim(concurrentTasks, concurrentTasks)
Dim tasks = New List(Of System.Threading.Tasks.Task)

For count = 1 To 20
    Dim taskNumber = count

    ' Blocks execution until another task can be started.
    ' This function also accepts a timeout in milliseconds
    Await semaphore.WaitAsync()

    ' Start a task
    Dim task = System.Threading.Tasks.Task.Run(Async Function()
        ' Execute long running code
        Try
           Debug.Print($"Task #{taskNumber} starting...")
           Await System.Threading.Tasks.Task.Delay(5000)
           Debug.Print($"  - Task #{taskNumber} completed!")
        Catch ex As Exception
           Throw
        Finally
           ' Signal that the task is completed 
           ' so another task can start
           semaphore.Release()
        End Try
    End Function)

    tasks.Add(task)
Next

Debug.Print($"Waiting for tasks to complete")

' Wait for all tasks to complete
Await System.Threading.Tasks.Task.WhenAll(tasks.ToArray)

Debug.Print($"All tasks completed!")

' example output:
'       Task #1 starting...
'       Task #2 starting...
'       Task #3 starting...
'       Task #4 starting...
'       Task #5 starting...
'         - Task #1 completed!
'         - Task #2 completed!
'       Task #6 starting...
'       Task #7 starting...
'         - Task #4 completed!
'         - Task #3 completed!
'         - Task #5 completed!
'       Task #8 starting...
'       Task #9 starting...
'       Task #10 starting...
'         - Task #7 completed!
'         - Task #6 completed!
'       Task #11 starting...
'       Task #12 starting...
'         - Task #9 completed!
'         - Task #10 completed!
'       Task #13 starting...
'       Task #14 starting...
'         - Task #8 completed!
'       Task #15 starting...
'         - Task #12 completed!
'         - Task #11 completed!
'       Task #16 starting...
'       Task #17 starting...
'         - Task #14 completed!
'         - Task #13 completed!
'         - Task #15 completed!
'       Task #19 starting...
'       Waiting for tasks to complete
'       Task #18 starting...
'       Task #20 starting...
'         - Task #17 completed!
'         - Task #16 completed!
'         - Task #19 completed!
'         - Task #20 completed!
'         - Task #18 completed!
'       All tasks completed!
			
				
					
				
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						' Task - Maximum Concurrency
 
Dim concurrentTasks = 5
Dim semaphore = New System.Threading.SemaphoreSlim(concurrentTasks, concurrentTasks)
Dim tasks = New List(Of System.Threading.Tasks.Task)
 
For count = 1 To 20
    Dim taskNumber = count
 
    ' Blocks execution until another task can be started.
    ' This function also accepts a timeout in milliseconds
    Await semaphore.WaitAsync()
 
    ' Start a task
    Dim task = System.Threading.Tasks.Task.Run(Async Function()
        ' Execute long running code
        Try
           Debug.Print($"Task #{taskNumber} starting...")
           Await System.Threading.Tasks.Task.Delay(5000)
           Debug.Print($"  - Task #{taskNumber} completed!")
        Catch ex As Exception
           Throw
        Finally
           ' Signal that the task is completed 
           ' so another task can start
           semaphore.Release()
        End Try
    End Function)
 
    tasks.Add(task)
Next
 
Debug.Print($"Waiting for tasks to complete")
 
' Wait for all tasks to complete
Await System.Threading.Tasks.Task.WhenAll(tasks.ToArray)
 
Debug.Print($"All tasks completed!")
 
' example output:
'       Task #1 starting...
'       Task #2 starting...
'       Task #3 starting...
'       Task #4 starting...
'       Task #5 starting...
'         - Task #1 completed!
'         - Task #2 completed!
'       Task #6 starting...
'       Task #7 starting...
'         - Task #4 completed!
'         - Task #3 completed!
'         - Task #5 completed!
'       Task #8 starting...
'       Task #9 starting...
'       Task #10 starting...
'         - Task #7 completed!
'         - Task #6 completed!
'       Task #11 starting...
'       Task #12 starting...
'         - Task #9 completed!
'         - Task #10 completed!
'       Task #13 starting...
'       Task #14 starting...
'         - Task #8 completed!
'       Task #15 starting...
'         - Task #12 completed!
'         - Task #11 completed!
'       Task #16 starting...
'       Task #17 starting...
'         - Task #14 completed!
'         - Task #13 completed!
'         - Task #15 completed!
'       Task #19 starting...
'       Waiting for tasks to complete
'       Task #18 starting...
'       Task #20 starting...
'         - Task #17 completed!
'         - Task #16 completed!
'         - Task #19 completed!
'         - Task #20 completed!
'         - Task #18 completed!
'       All tasks completed!

2. Task – Maximum Concurrency – Return Value

The example below demonstrates how to start and run multiple tasks with a maximum concurrency. In this example, a value is returned and retrieved from the tasks

The functions shown in the example below are called asynchronously, but they can also be called synchronously.



		
		
			2. Task - Maximum Concurrency - Return Value
			
Visual Basic .NET
			
			' Task - Maximum Concurrency - Return Value

Public Class Part
    Public Property PartName As String
    Public Property PartId As Integer
End Class

Dim concurrentTasks = 5
Dim semaphore = New System.Threading.SemaphoreSlim(concurrentTasks, concurrentTasks)
Dim tasks = New List(Of System.Threading.Tasks.Task(Of Part))

For count = 1 To 20
    Dim taskNumber = count

    ' Blocks execution until another task can be started.
    ' This function also accepts a timeout in milliseconds
    Await semaphore.WaitAsync()

    ' Start a task
    Dim task = System.Threading.Tasks.Task.Run(Async Function()
        ' Execute long running code
        Try
           Debug.Print($"Task #{taskNumber} starting...")
           Await System.Threading.Tasks.Task.Delay(5000)
           Debug.Print($"  - Task #{taskNumber} completed!")

           ' Return result
           Return New Part With {
                .PartId = taskNumber,
                .PartName = $"Part #{taskNumber}"
           }
        Catch ex As Exception
           Throw
        Finally
           ' Signal that the task is completed 
           ' so another task can start
           semaphore.Release()
        End Try
    End Function)

    tasks.Add(task)
Next

Debug.Print($"Waiting for tasks to complete")

' Wait for all tasks to complete
Await System.Threading.Tasks.Task.WhenAll(tasks.ToArray)

Debug.Print($"All tasks completed!")

Debug.Print("")

' Get the results 
For Each task In tasks
    Dim part = task.Result
    Debug.Print($"Id: {part.PartId}, Name: {part.PartName}")
Next

' example output:
'       Task #1 starting...
'       Task #2 starting...
'       Task #3 starting...
'       Task #4 starting...
'       Task #5 starting...
'         - Task #3 completed!
'         - Task #2 completed!
'         - Task #5 completed!
'         - Task #1 completed!
'       Task #8 starting...
'       Task #7 starting...
'       Task #6 starting...
'         - Task #4 completed!
'       Task #9 starting...
'       Task #10 starting...
'         - Task #8 completed!
'       Task #11 starting...
'         - Task #7 completed!
'       Task #12 starting...
'         - Task #6 completed!
'       Task #13 starting...
'         - Task #10 completed!
'         - Task #9 completed!
'       Task #14 starting...
'       Task #15 starting...
'         - Task #11 completed!
'       Task #16 starting...
'         - Task #12 completed!
'       Task #17 starting...
'         - Task #13 completed!
'       Task #18 starting...
'         - Task #15 completed!
'         - Task #14 completed!
'       Task #19 starting...
'       Waiting for tasks to complete
'       Task #20 starting...
'         - Task #16 completed!
'         - Task #17 completed!
'         - Task #18 completed!
'         - Task #19 completed!
'         - Task #20 completed!
'       All tasks completed!
'   
'       Id: 1, Name: Part #1
'       Id: 2, Name: Part #2
'       Id: 3, Name: Part #3
'       Id: 4, Name: Part #4
'       Id: 5, Name: Part #5
'       Id: 6, Name: Part #6
'       Id: 7, Name: Part #7
'       Id: 8, Name: Part #8
'       Id: 9, Name: Part #9
'       Id: 10, Name: Part #10
'       Id: 11, Name: Part #11
'       Id: 12, Name: Part #12
'       Id: 13, Name: Part #13
'       Id: 14, Name: Part #14
'       Id: 15, Name: Part #15
'       Id: 16, Name: Part #16
'       Id: 17, Name: Part #17
'       Id: 18, Name: Part #18
'       Id: 19, Name: Part #19
'       Id: 20, Name: Part #20
			
				
					
				
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						' Task - Maximum Concurrency - Return Value
 
Public Class Part
    Public Property PartName As String
    Public Property PartId As Integer
End Class
 
Dim concurrentTasks = 5
Dim semaphore = New System.Threading.SemaphoreSlim(concurrentTasks, concurrentTasks)
Dim tasks = New List(Of System.Threading.Tasks.Task(Of Part))
 
For count = 1 To 20
    Dim taskNumber = count
 
    ' Blocks execution until another task can be started.
    ' This function also accepts a timeout in milliseconds
    Await semaphore.WaitAsync()
 
    ' Start a task
    Dim task = System.Threading.Tasks.Task.Run(Async Function()
        ' Execute long running code
        Try
           Debug.Print($"Task #{taskNumber} starting...")
           Await System.Threading.Tasks.Task.Delay(5000)
           Debug.Print($"  - Task #{taskNumber} completed!")
 
           ' Return result
           Return New Part With {
                .PartId = taskNumber,
                .PartName = $"Part #{taskNumber}"
           }
        Catch ex As Exception
           Throw
        Finally
           ' Signal that the task is completed 
           ' so another task can start
           semaphore.Release()
        End Try
    End Function)
 
    tasks.Add(task)
Next
 
Debug.Print($"Waiting for tasks to complete")
 
' Wait for all tasks to complete
Await System.Threading.Tasks.Task.WhenAll(tasks.ToArray)
 
Debug.Print($"All tasks completed!")
 
Debug.Print("")
 
' Get the results 
For Each task In tasks
    Dim part = task.Result
    Debug.Print($"Id: {part.PartId}, Name: {part.PartName}")
Next
 
' example output:
'       Task #1 starting...
'       Task #2 starting...
'       Task #3 starting...
'       Task #4 starting...
'       Task #5 starting...
'         - Task #3 completed!
'         - Task #2 completed!
'         - Task #5 completed!
'         - Task #1 completed!
'       Task #8 starting...
'       Task #7 starting...
'       Task #6 starting...
'         - Task #4 completed!
'       Task #9 starting...
'       Task #10 starting...
'         - Task #8 completed!
'       Task #11 starting...
'         - Task #7 completed!
'       Task #12 starting...
'         - Task #6 completed!
'       Task #13 starting...
'         - Task #10 completed!
'         - Task #9 completed!
'       Task #14 starting...
'       Task #15 starting...
'         - Task #11 completed!
'       Task #16 starting...
'         - Task #12 completed!
'       Task #17 starting...
'         - Task #13 completed!
'       Task #18 starting...
'         - Task #15 completed!
'         - Task #14 completed!
'       Task #19 starting...
'       Waiting for tasks to complete
'       Task #20 starting...
'         - Task #16 completed!
'         - Task #17 completed!
'         - Task #18 completed!
'         - Task #19 completed!
'         - Task #20 completed!
'       All tasks completed!
'   
'       Id: 1, Name: Part #1
'       Id: 2, Name: Part #2
'       Id: 3, Name: Part #3
'       Id: 4, Name: Part #4
'       Id: 5, Name: Part #5
'       Id: 6, Name: Part #6
'       Id: 7, Name: Part #7
'       Id: 8, Name: Part #8
'       Id: 9, Name: Part #9
'       Id: 10, Name: Part #10
'       Id: 11, Name: Part #11
'       Id: 12, Name: Part #12
'       Id: 13, Name: Part #13
'       Id: 14, Name: Part #14
'       Id: 15, Name: Part #15
'       Id: 16, Name: Part #16
'       Id: 17, Name: Part #17
'       Id: 18, Name: Part #18
'       Id: 19, Name: Part #19
'       Id: 20, Name: Part #20

3. More Examples

Below is a full example of the process demonstrated on this page!



		
		
			More Examples
			
Visual Basic .NET
			
			' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Dec 4, 2020
'    Taken From: http://programmingnotes.org/
'    File: Program.vb
'    Description: The following demonstrates creating a task pool
' ============================================================================
Option Strict On
Option Explicit On
Imports System

Public Module Program
    Public Class Part
        Public Property PartName As String
        Public Property PartId As Integer
    End Class

    Sub Main(args As String())
        Try
            'TaskSub.Wait()
            TaskFunction.Wait()
        Catch ex As Exception
            Display(ex.ToString)
        Finally
            Console.ReadLine()
        End Try
    End Sub

    Public Async Function TaskFunction() As Task(Of List(Of Part))
        Dim concurrentTasks = 5
        Dim semaphore = New System.Threading.SemaphoreSlim(concurrentTasks, concurrentTasks)
        Dim tasks = New List(Of System.Threading.Tasks.Task(Of Part))

        For count = 1 To 20
            Dim taskNumber = count

            ' Blocks execution until another task can be started.
            ' This function also accepts a timeout in milliseconds
            Await semaphore.WaitAsync()

            ' Start a task
            Dim task = System.Threading.Tasks.Task.Run(Async Function()
                                                           ' Execute long running code
                                                           Try
                                                               Display($"Task #{taskNumber} starting...")
                                                               Await System.Threading.Tasks.Task.Delay(5000)
                                                               Display($"  - Task #{taskNumber} completed!")

                                                               Return New Part With {
                                                                    .PartId = taskNumber,
                                                                    .PartName = $"Part #{taskNumber}"
                                                               }
                                                           Catch ex As Exception
                                                               Throw
                                                           Finally
                                                               ' Signal that the task is completed 
                                                               ' so another task can start
                                                               semaphore.Release()
                                                           End Try
                                                       End Function)

            tasks.Add(task)
        Next

        Display($"Waiting for tasks to complete")

        ' Wait for all tasks to complete
        Await System.Threading.Tasks.Task.WhenAll(tasks.ToArray)

        Display($"All tasks completed!")

        Display("")

        ' Get the results 
        For Each task In tasks
            Dim part = task.Result
            Display($"Id: {part.PartId}, Name: {part.PartName}")
        Next

        Return tasks.Select(Function(task) task.Result).ToList
    End Function

    Public Async Function TaskSub() As Task
        Dim concurrentTasks = 5
        Dim semaphore = New System.Threading.SemaphoreSlim(concurrentTasks, concurrentTasks)
        Dim tasks = New List(Of System.Threading.Tasks.Task)

        For count = 1 To 20
            Dim taskNumber = count

            ' Blocks execution until another task can be started.
            ' This function also accepts a timeout in milliseconds
            Await semaphore.WaitAsync()

            ' Start a task
            Dim task = System.Threading.Tasks.Task.Run(Async Function()
                                                           ' Execute long running code
                                                           Try
                                                               Display($"Task #{taskNumber} starting...")
                                                               Await System.Threading.Tasks.Task.Delay(5000)
                                                               Display($"  - Task #{taskNumber} completed!")
                                                           Catch ex As Exception
                                                               Throw
                                                           Finally
                                                               ' Signal that the task is completed 
                                                               ' so another task can start
                                                               semaphore.Release()
                                                           End Try
                                                       End Function)

            tasks.Add(task)
        Next

        Display($"Waiting for tasks to complete")

        ' Wait for all tasks to complete
        Await System.Threading.Tasks.Task.WhenAll(tasks.ToArray)

        Display($"All tasks completed!")
    End Function

    Public Sub Display(message As String)
        Console.WriteLine(message)
        Debug.Print(message)
    End Sub
End Module ' http://programmingnotes.org/
			
				
					
				
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						' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Dec 4, 2020
'    Taken From: http://programmingnotes.org/
'    File: Program.vb
'    Description: The following demonstrates creating a task pool
' ============================================================================
Option Strict On
Option Explicit On
Imports System
 
Public Module Program
    Public Class Part
        Public Property PartName As String
        Public Property PartId As Integer
    End Class
 
    Sub Main(args As String())
        Try
            'TaskSub.Wait()
            TaskFunction.Wait()
        Catch ex As Exception
            Display(ex.ToString)
        Finally
            Console.ReadLine()
        End Try
    End Sub
 
    Public Async Function TaskFunction() As Task(Of List(Of Part))
        Dim concurrentTasks = 5
        Dim semaphore = New System.Threading.SemaphoreSlim(concurrentTasks, concurrentTasks)
        Dim tasks = New List(Of System.Threading.Tasks.Task(Of Part))
 
        For count = 1 To 20
            Dim taskNumber = count
 
            ' Blocks execution until another task can be started.
            ' This function also accepts a timeout in milliseconds
            Await semaphore.WaitAsync()
 
            ' Start a task
            Dim task = System.Threading.Tasks.Task.Run(Async Function()
                                                           ' Execute long running code
                                                           Try
                                                               Display($"Task #{taskNumber} starting...")
                                                               Await System.Threading.Tasks.Task.Delay(5000)
                                                               Display($"  - Task #{taskNumber} completed!")
 
                                                               Return New Part With {
                                                                    .PartId = taskNumber,
                                                                    .PartName = $"Part #{taskNumber}"
                                                               }
                                                           Catch ex As Exception
                                                               Throw
                                                           Finally
                                                               ' Signal that the task is completed 
                                                               ' so another task can start
                                                               semaphore.Release()
                                                           End Try
                                                       End Function)
 
            tasks.Add(task)
        Next
 
        Display($"Waiting for tasks to complete")
 
        ' Wait for all tasks to complete
        Await System.Threading.Tasks.Task.WhenAll(tasks.ToArray)
 
        Display($"All tasks completed!")
 
        Display("")
 
        ' Get the results 
        For Each task In tasks
            Dim part = task.Result
            Display($"Id: {part.PartId}, Name: {part.PartName}")
        Next
 
        Return tasks.Select(Function(task) task.Result).ToList
    End Function
 
    Public Async Function TaskSub() As Task
        Dim concurrentTasks = 5
        Dim semaphore = New System.Threading.SemaphoreSlim(concurrentTasks, concurrentTasks)
        Dim tasks = New List(Of System.Threading.Tasks.Task)
 
        For count = 1 To 20
            Dim taskNumber = count
 
            ' Blocks execution until another task can be started.
            ' This function also accepts a timeout in milliseconds
            Await semaphore.WaitAsync()
 
            ' Start a task
            Dim task = System.Threading.Tasks.Task.Run(Async Function()
                                                           ' Execute long running code
                                                           Try
                                                               Display($"Task #{taskNumber} starting...")
                                                               Await System.Threading.Tasks.Task.Delay(5000)
                                                               Display($"  - Task #{taskNumber} completed!")
                                                           Catch ex As Exception
                                                               Throw
                                                           Finally
                                                               ' Signal that the task is completed 
                                                               ' so another task can start
                                                               semaphore.Release()
                                                           End Try
                                                       End Function)
 
            tasks.Add(task)
        Next
 
        Display($"Waiting for tasks to complete")
 
        ' Wait for all tasks to complete
        Await System.Threading.Tasks.Task.WhenAll(tasks.ToArray)
 
        Display($"All tasks completed!")
    End Function
 
    Public Sub Display(message As String)
        Console.WriteLine(message)
        Debug.Print(message)
    End Sub
End Module ' http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

VB.NET || How To Convert Bytes To Kilobytes, Megabytes, Gigabytes, Terabytes Using VB.NET

December 03, 2020 admin No comments

The following is a module with functions which demonstrates how to convert bytes to decimal formats like kilobytes, megabytes, gigabytes, terabytes, petabytes, exabytes, zettabytes, and yottabytes, as well as binary formats like kibibytes, mebibytes, gibibytes, tebibytes, pebibytes, exbibytes, zebibytes, and yobibytes using VB.NET.

The function demonstrated on this page follows the IEC standard, which means:

• 1 kilobyte = 1000 bytes (Decimal) • 1 kibibyte = 1024 bytes (Binary)

This function allows you to convert bytes to a measurement unit, a measurement unit to bytes, and allows to convert from one measurement unit to another measurement unit.

1. Convert Bytes To Measurement Unit

The example below demonstrates the use of ‘Utils.Bytes.FromTo‘ to convert bytes to a measurement unit.

The optional function parameter allows you to specify the decimal places.



		
		
			1. Convert Bytes To Measurement Unit
			
Visual Basic .NET
			
			' Convert Bytes To Measurement Unit

' Declare values to convert
Dim values = {2287879, 536870912, 1073741824}

' Convert values
For Each value In values
    ' Convert bytes to megabyte
    Dim mb = Utils.Bytes.FromTo(Utils.Bytes.Unit.Byte, value, Utils.Bytes.Unit.Megabyte)

    ' Convert bytes to mebibyte
    Dim mib = Utils.Bytes.FromTo(Utils.Bytes.Unit.Byte, value, Utils.Bytes.Unit.Mebibyte)

    ' Display the converted values
    Debug.Print($"Bytes: {value}, Megabyte: {mb}, Mebibyte: {mib}")
Next

' expected output:
'    Bytes: 2287879, Megabyte: 2.287879, Mebibyte: 2.18189144134521484375
'    Bytes: 536870912, Megabyte: 536.870912, Mebibyte: 512
'    Bytes: 1073741824, Megabyte: 1073.741824, Mebibyte: 1024
			
				
					
				
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						' Convert Bytes To Measurement Unit
 
' Declare values to convert
Dim values = {2287879, 536870912, 1073741824}
 
' Convert values
For Each value In values
    ' Convert bytes to megabyte
    Dim mb = Utils.Bytes.FromTo(Utils.Bytes.Unit.Byte, value, Utils.Bytes.Unit.Megabyte)
 
    ' Convert bytes to mebibyte
    Dim mib = Utils.Bytes.FromTo(Utils.Bytes.Unit.Byte, value, Utils.Bytes.Unit.Mebibyte)
 
    ' Display the converted values
    Debug.Print($"Bytes: {value}, Megabyte: {mb}, Mebibyte: {mib}")
Next
 
' expected output:
'    Bytes: 2287879, Megabyte: 2.287879, Mebibyte: 2.18189144134521484375
'    Bytes: 536870912, Megabyte: 536.870912, Mebibyte: 512
'    Bytes: 1073741824, Megabyte: 1073.741824, Mebibyte: 1024

2. Convert Measurement Unit To Bytes

The example below demonstrates the use of ‘Utils.Bytes.FromTo‘ to convert a measurement unit to bytes.

The optional function parameter allows you to specify the decimal places.



		
		
			2. Convert Measurement Unit To Bytes
			
Visual Basic .NET
			
			' Convert Measurement Unit To Bytes

' Declare values to convert
Dim values = {1, 0.5D, 10.75D}

' Convert values
For Each value In values
    ' Convert gibibyte to byte
    Dim bytes = Utils.Bytes.FromTo(Utils.Bytes.Unit.Gibibyte, value, Utils.Bytes.Unit.Byte)

    ' Display the converted values
    Debug.Print($"Gibibyte: {value}, Bytes: {bytes}")
Next

' expected output:
'    Gibibyte: 1, Bytes: 1073741824
'    Gibibyte: 0.5, Bytes: 536870912.0
'    Gibibyte: 10.75, Bytes: 11542724608.00
			
				
					
				
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						' Convert Measurement Unit To Bytes
 
' Declare values to convert
Dim values = {1, 0.5D, 10.75D}
 
' Convert values
For Each value In values
    ' Convert gibibyte to byte
    Dim bytes = Utils.Bytes.FromTo(Utils.Bytes.Unit.Gibibyte, value, Utils.Bytes.Unit.Byte)
 
    ' Display the converted values
    Debug.Print($"Gibibyte: {value}, Bytes: {bytes}")
Next
 
' expected output:
'    Gibibyte: 1, Bytes: 1073741824
'    Gibibyte: 0.5, Bytes: 536870912.0
'    Gibibyte: 10.75, Bytes: 11542724608.00

3. Convert Measurement Unit To Measurement Unit

The example below demonstrates the use of ‘Utils.Bytes.FromTo‘ to convert a measurement unit to another measurement unit.

The optional function parameter allows you to specify the decimal places.



		
		
			3. Convert Measurement Unit To Measurement Unit
			
Visual Basic .NET
			
			' Convert Measurement Unit To Measurement Unit

' Declare values to convert
Dim values = {1991, 1987, 28.31D, 19.22D}

' Convert values
For Each value In values
    ' Convert value from one unit to another
    Dim size = Utils.Bytes.FromTo(Utils.Bytes.Unit.Gigabyte, value, Utils.Bytes.Unit.Terabyte)

    ' Display the converted values
    Debug.Print($"Gigabyte: {value}, Terabyte: {size}")
Next

' expected output:
'    Gigabyte: 1991, Terabyte: 1.991
'    Gigabyte: 1987, Terabyte: 1.987
'    Gigabyte: 28.31, Terabyte: 0.02831
'    Gigabyte: 19.22, Terabyte: 0.01922
			
				
					
				
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						' Convert Measurement Unit To Measurement Unit
 
' Declare values to convert
Dim values = {1991, 1987, 28.31D, 19.22D}
 
' Convert values
For Each value In values
    ' Convert value from one unit to another
    Dim size = Utils.Bytes.FromTo(Utils.Bytes.Unit.Gigabyte, value, Utils.Bytes.Unit.Terabyte)
 
    ' Display the converted values
    Debug.Print($"Gigabyte: {value}, Terabyte: {size}")
Next
 
' expected output:
'    Gigabyte: 1991, Terabyte: 1.991
'    Gigabyte: 1987, Terabyte: 1.987
'    Gigabyte: 28.31, Terabyte: 0.02831
'    Gigabyte: 19.22, Terabyte: 0.01922

4. Utils Namespace

The following is the Utils Namespace. Include this in your project to start using!



		
		
			Utils Namespace
			
Visual Basic .NET
			
			' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Dec 3, 2020
'    Taken From: http://programmingnotes.org/
'    File: Utils.vb
'    Description: Handles general utility functions
' ============================================================================
Option Strict On
Option Explicit On

Namespace Global.Utils
    Namespace Bytes
        Public Module modBytes
            Public Enum Unit
                [Byte]

                ' Decimal 
                Kilobyte
                Megabyte
                Gigabyte
                Terabyte
                Petabyte
                Exabyte
                Zettabyte
                Yottabyte

                ' Binary 
                Kibibyte
                Mebibyte
                Gibibyte
                Tebibyte
                Pebibyte
                Exbibyte
                Zebibyte
                Yobibyte
            End Enum

            ''' <summary>
            ''' Converts a measurement 'Unit' to another measurement 'Unit'
            ''' </summary>
            ''' <param name="unitFrom">The measurement unit converting from</param> 
            ''' <param name="sizeFrom">The size of the 'from' measurement unit</param> 
            ''' <param name="unitTo">The measurement unit to convert to</param> 
            ''' <param name="decimalPlaces">The decimal places to round to</param> 
            ''' <returns>The value converted to the specified measurement unit</returns>
            Public Function FromTo(unitFrom As Unit, sizeFrom As Decimal, unitTo As Unit _
                        , Optional decimalPlaces As Integer? = Nothing) As Decimal
                Dim result = sizeFrom
                If unitFrom <> unitTo Then
                    If unitFrom = Unit.Byte Then
                        result = ConvertTo(unitTo, sizeFrom, decimalPlaces)
                    ElseIf unitTo = Unit.Byte Then
                        result = ConvertFrom(unitFrom, sizeFrom, decimalPlaces)
                    Else
                        result = ConvertTo(unitTo, ConvertFrom(unitFrom, sizeFrom), decimalPlaces)
                    End If
                End If
                Return result
            End Function

            Private Enum Conversion
                From
                [To]
            End Enum

            ' Converts bytes to a measurement unit
            Private Function ConvertTo(unit As Unit, bytes As Decimal _
                        , Optional decimalPlaces As Integer? = Nothing) As Decimal
                Return Convert(Conversion.To, bytes, unit, decimalPlaces)
            End Function

            ' Converts a measurement unit to bytes
            Private Function ConvertFrom(unit As Unit, bytes As Decimal _
                        , Optional decimalPlaces As Integer? = Nothing) As Decimal
                Return Convert(Conversion.From, bytes, unit, decimalPlaces)
            End Function

            Private Function Convert(operation As Conversion, bytes As Decimal, unit As Unit _
                        , decimalPlaces As Integer?) As Decimal
                ' Get the unit type definition
                Dim definition = GetDefinition(unit)
                If definition Is Nothing Then
                    Throw New ArgumentException($"Unknown unit type: {unit}", NameOf(unit))
                End If
                ' Get the unit value
                Dim value = definition.Value

                ' Calculate the result
                Dim result = If(operation = Conversion.To, bytes / value, bytes * value)
                If decimalPlaces.HasValue Then
                    result = Math.Round(result, decimalPlaces.Value, MidpointRounding.AwayFromZero)
                End If
                Return result
            End Function

            Public Enum Prefix
                [Decimal]
                Binary
            End Enum

            Public Class Definition
                Public Property Prefix As Prefix
                Public Property OrderOfMagnitude As Integer
                Public ReadOnly Property Multiple As Decimal
                    Get
                        Return If(Prefix = Prefix.Decimal, 1000, 1024)
                    End Get
                End Property
                Public ReadOnly Property Value As Decimal
                    Get
                        Return CDec(Math.Pow(Multiple, OrderOfMagnitude))
                    End Get
                End Property
            End Class

            Public Function GetDefinition(unit As Unit) As Definition
                Dim definitions = GetDefinitions()
                Return If(definitions.ContainsKey(unit), definitions(unit), Nothing)
            End Function

            Public Function GetDefinitions() As Dictionary(Of Unit, Definition)
                ' Create and add definitions
                Static definitions As Dictionary(Of Unit, Definition)
                If definitions Is Nothing Then
                    definitions = New Dictionary(Of Unit, Definition)
                    ' Place units in order of magnitude

                    ' Decimal units
                    Dim decimals = {
                        Unit.Kilobyte, Unit.Megabyte, Unit.Gigabyte, Unit.Terabyte _
                        , Unit.Petabyte, Unit.Exabyte, Unit.Zettabyte, Unit.Yottabyte
                    }
                    ' Binary units
                    Dim binary = {
                        Unit.Kibibyte, Unit.Mebibyte, Unit.Gibibyte, Unit.Tebibyte _
                        , Unit.Pebibyte, Unit.Exbibyte, Unit.Zebibyte, Unit.Yobibyte
                    }
                    AddDefinitions(definitions, Prefix.Decimal, decimals)
                    AddDefinitions(definitions, Prefix.Binary, binary)
                End If
                Return definitions
            End Function

            Private Sub AddDefinitions(definitions As Dictionary(Of Unit, Definition) _
                                       , prefix As Prefix, units As IEnumerable(Of Unit))
                For index = 0 To units.Count - 1
                    Dim unit = units(index)
                    If Not definitions.ContainsKey(unit) Then
                        definitions.Add(unit, New Definition With {
                            .Prefix = prefix, .OrderOfMagnitude = index + 1
                        })
                    End If
                Next
            End Sub
        End Module
    End Namespace
End Namespace ' http://programmingnotes.org/
			
				
					
				
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						' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Dec 3, 2020
'    Taken From: http://programmingnotes.org/
'    File: Utils.vb
'    Description: Handles general utility functions
' ============================================================================
Option Strict On
Option Explicit On
 
Namespace Global.Utils
    Namespace Bytes
        Public Module modBytes
            Public Enum Unit
                [Byte]
 
                ' Decimal 
                Kilobyte
                Megabyte
                Gigabyte
                Terabyte
                Petabyte
                Exabyte
                Zettabyte
                Yottabyte
 
                ' Binary 
                Kibibyte
                Mebibyte
                Gibibyte
                Tebibyte
                Pebibyte
                Exbibyte
                Zebibyte
                Yobibyte
            End Enum
 
            ''' <summary>
            ''' Converts a measurement 'Unit' to another measurement 'Unit'
            ''' </summary>
            ''' <param name="unitFrom">The measurement unit converting from</param> 
            ''' <param name="sizeFrom">The size of the 'from' measurement unit</param> 
            ''' <param name="unitTo">The measurement unit to convert to</param> 
            ''' <param name="decimalPlaces">The decimal places to round to</param> 
            ''' <returns>The value converted to the specified measurement unit</returns>
            Public Function FromTo(unitFrom As Unit, sizeFrom As Decimal, unitTo As Unit _
                        , Optional decimalPlaces As Integer? = Nothing) As Decimal
                Dim result = sizeFrom
                If unitFrom <> unitTo Then
                    If unitFrom = Unit.Byte Then
                        result = ConvertTo(unitTo, sizeFrom, decimalPlaces)
                    ElseIf unitTo = Unit.Byte Then
                        result = ConvertFrom(unitFrom, sizeFrom, decimalPlaces)
                    Else
                        result = ConvertTo(unitTo, ConvertFrom(unitFrom, sizeFrom), decimalPlaces)
                    End If
                End If
                Return result
            End Function
 
            Private Enum Conversion
                From
                [To]
            End Enum
 
            ' Converts bytes to a measurement unit
            Private Function ConvertTo(unit As Unit, bytes As Decimal _
                        , Optional decimalPlaces As Integer? = Nothing) As Decimal
                Return Convert(Conversion.To, bytes, unit, decimalPlaces)
            End Function
 
            ' Converts a measurement unit to bytes
            Private Function ConvertFrom(unit As Unit, bytes As Decimal _
                        , Optional decimalPlaces As Integer? = Nothing) As Decimal
                Return Convert(Conversion.From, bytes, unit, decimalPlaces)
            End Function
 
            Private Function Convert(operation As Conversion, bytes As Decimal, unit As Unit _
                        , decimalPlaces As Integer?) As Decimal
                ' Get the unit type definition
                Dim definition = GetDefinition(unit)
                If definition Is Nothing Then
                    Throw New ArgumentException($"Unknown unit type: {unit}", NameOf(unit))
                End If
                ' Get the unit value
                Dim value = definition.Value
 
                ' Calculate the result
                Dim result = If(operation = Conversion.To, bytes / value, bytes * value)
                If decimalPlaces.HasValue Then
                    result = Math.Round(result, decimalPlaces.Value, MidpointRounding.AwayFromZero)
                End If
                Return result
            End Function
 
            Public Enum Prefix
                [Decimal]
                Binary
            End Enum
 
            Public Class Definition
                Public Property Prefix As Prefix
                Public Property OrderOfMagnitude As Integer
                Public ReadOnly Property Multiple As Decimal
                    Get
                        Return If(Prefix = Prefix.Decimal, 1000, 1024)
                    End Get
                End Property
                Public ReadOnly Property Value As Decimal
                    Get
                        Return CDec(Math.Pow(Multiple, OrderOfMagnitude))
                    End Get
                End Property
            End Class
 
            Public Function GetDefinition(unit As Unit) As Definition
                Dim definitions = GetDefinitions()
                Return If(definitions.ContainsKey(unit), definitions(unit), Nothing)
            End Function
 
            Public Function GetDefinitions() As Dictionary(Of Unit, Definition)
                ' Create and add definitions
                Static definitions As Dictionary(Of Unit, Definition)
                If definitions Is Nothing Then
                    definitions = New Dictionary(Of Unit, Definition)
                    ' Place units in order of magnitude
 
                    ' Decimal units
                    Dim decimals = {
                        Unit.Kilobyte, Unit.Megabyte, Unit.Gigabyte, Unit.Terabyte _
                        , Unit.Petabyte, Unit.Exabyte, Unit.Zettabyte, Unit.Yottabyte
                    }
                    ' Binary units
                    Dim binary = {
                        Unit.Kibibyte, Unit.Mebibyte, Unit.Gibibyte, Unit.Tebibyte _
                        , Unit.Pebibyte, Unit.Exbibyte, Unit.Zebibyte, Unit.Yobibyte
                    }
                    AddDefinitions(definitions, Prefix.Decimal, decimals)
                    AddDefinitions(definitions, Prefix.Binary, binary)
                End If
                Return definitions
            End Function
 
            Private Sub AddDefinitions(definitions As Dictionary(Of Unit, Definition) _
                                       , prefix As Prefix, units As IEnumerable(Of Unit))
                For index = 0 To units.Count - 1
                    Dim unit = units(index)
                    If Not definitions.ContainsKey(unit) Then
                        definitions.Add(unit, New Definition With {
                            .Prefix = prefix, .OrderOfMagnitude = index + 1
                        })
                    End If
                Next
            End Sub
        End Module
    End Namespace
End Namespace ' http://programmingnotes.org/

5. More Examples

Below are more examples demonstrating the use of the ‘Utils‘ Namespace. Don’t forget to include the module when running the examples!



		
		
			More Examples
			
Visual Basic .NET
			
			' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Dec 3, 2020
'    Taken From: http://programmingnotes.org/
'    File: Program.vb
'    Description: The following demonstrates the use of the Utils Namespace
' ============================================================================
Option Strict On
Option Explicit On
Imports System

Public Module Program
    Sub Main(args As String())
        Try
            ' Declare values to convert
            Dim values = {2287879, 536870912, 1073741824}

            ' Convert values
            For Each value In values
                ' Convert bytes to megabyte
                Dim mb = Utils.Bytes.FromTo(Utils.Bytes.Unit.Byte, value, Utils.Bytes.Unit.Megabyte)

                ' Convert bytes to mebibyte
                Dim mib = Utils.Bytes.FromTo(Utils.Bytes.Unit.Byte, value, Utils.Bytes.Unit.Mebibyte)

                ' Display the converted values
                Display($"Bytes: {value}, Megabyte: {mb}, Mebibyte: {mib}")
            Next

            Display("")

            ' Declare values to convert
            Dim values2 = {1, 0.5D, 10.75D}

            ' Convert values
            For Each value In values2
                ' Convert gibibyte to byte
                Dim bytes = Utils.Bytes.FromTo(Utils.Bytes.Unit.Gibibyte, value, Utils.Bytes.Unit.Byte)

                ' Display the converted values
                Display($"Gibibyte: {value}, Bytes: {bytes}")
            Next

            Display("")

            ' Declare values to convert
            Dim values3 = {1991, 1987, 28.31D, 19.22D}

            ' Convert values
            For Each value In values3
                ' Convert value from one unit to another
                Dim size = Utils.Bytes.FromTo(Utils.Bytes.Unit.Gigabyte, value, Utils.Bytes.Unit.Terabyte)

                ' Display the converted values
                Display($"Gigabyte: {value}, Terabyte: {size}")
            Next
        Catch ex As Exception
            Display(ex.ToString)
        Finally
            Console.ReadLine()
        End Try
    End Sub

    Public Sub Display(message As String)
        Console.WriteLine(message)
        Debug.Print(message)
    End Sub
End Module ' http://programmingnotes.org/
			
				
					
				
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						' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Dec 3, 2020
'    Taken From: http://programmingnotes.org/
'    File: Program.vb
'    Description: The following demonstrates the use of the Utils Namespace
' ============================================================================
Option Strict On
Option Explicit On
Imports System
 
Public Module Program
    Sub Main(args As String())
        Try
            ' Declare values to convert
            Dim values = {2287879, 536870912, 1073741824}
 
            ' Convert values
            For Each value In values
                ' Convert bytes to megabyte
                Dim mb = Utils.Bytes.FromTo(Utils.Bytes.Unit.Byte, value, Utils.Bytes.Unit.Megabyte)
 
                ' Convert bytes to mebibyte
                Dim mib = Utils.Bytes.FromTo(Utils.Bytes.Unit.Byte, value, Utils.Bytes.Unit.Mebibyte)
 
                ' Display the converted values
                Display($"Bytes: {value}, Megabyte: {mb}, Mebibyte: {mib}")
            Next
 
            Display("")
 
            ' Declare values to convert
            Dim values2 = {1, 0.5D, 10.75D}
 
            ' Convert values
            For Each value In values2
                ' Convert gibibyte to byte
                Dim bytes = Utils.Bytes.FromTo(Utils.Bytes.Unit.Gibibyte, value, Utils.Bytes.Unit.Byte)
 
                ' Display the converted values
                Display($"Gibibyte: {value}, Bytes: {bytes}")
            Next
 
            Display("")
 
            ' Declare values to convert
            Dim values3 = {1991, 1987, 28.31D, 19.22D}
 
            ' Convert values
            For Each value In values3
                ' Convert value from one unit to another
                Dim size = Utils.Bytes.FromTo(Utils.Bytes.Unit.Gigabyte, value, Utils.Bytes.Unit.Terabyte)
 
                ' Display the converted values
                Display($"Gigabyte: {value}, Terabyte: {size}")
            Next
        Catch ex As Exception
            Display(ex.ToString)
        Finally
            Console.ReadLine()
        End Try
    End Sub
 
    Public Sub Display(message As String)
        Console.WriteLine(message)
        Debug.Print(message)
    End Sub
End Module ' http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

VB.NET || How To Parse A Delimited CSV File Using VB.NET

December 02, 2020 admin No comments

The following is a module with functions which demonstrates how to parse a delimited CSV file using VB.NET.

The function demonstrated on this page uses FileIO.TextFieldParser to parse values in a CSV file.

This function parses a CSV file and returns its results as a List. Each List index represents a line in the CSV file, with each item in the list representing a record contained on that line.

1. Parse CSV File

The example below demonstrates the use of ‘Utils.ParseCsv‘ to parse a CSV file and return its results as a List.

The optional function parameter allows you to specify the delimiters. Default delimiter is a comma (,).

Sample CSV used in this example is the following:



		
		
			Kenneth,Perkins,120 jefferson st.,Riverside, NJ, 08075
Jack,McGinnis,220 hobo Av.,Phila, PA,09119
"Jennifer ""Da Man""",Repici,120 Jefferson St.,Riverside, NJ,08075
Stephen,Tyler,"7452 Terrace ""At the Plaza"" road",SomeTown,SD, 91234
,Blankman,,SomeTown, SD, 00298
"Joan ""the bone"", Anne",Jet,"9th, at Terrace plc",Desert City,CO,00123
			
				
					
				
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						Kenneth,Perkins,120 jefferson st.,Riverside, NJ, 08075
Jack,McGinnis,220 hobo Av.,Phila, PA,09119
"Jennifer ""Da Man""",Repici,120 Jefferson St.,Riverside, NJ,08075
Stephen,Tyler,"7452 Terrace ""At the Plaza"" road",SomeTown,SD, 91234
,Blankman,,SomeTown, SD, 00298
"Joan ""the bone"", Anne",Jet,"9th, at Terrace plc",Desert City,CO,00123



		
		
			1. Parse CSV File
			
Visual Basic .NET
			
			' Parse CSV File

' Read file into byte array
Dim fileBytes As Byte()

' Parse the contents of the file into a list
Dim fileContents = Utils.ParseCsv(fileBytes)

' Display the contents of the file
For lineIndex = 0 To fileContents.Count - 1
    Dim line = fileContents(lineIndex)

    Debug.Print($"Line #{lineIndex + 1}")
    For Each item In line
        Debug.Print($"  Item: {item}")
    Next
Next

' expected output:
'    Line #1
'      Item: Kenneth
'      Item: Perkins
'      Item: 120 jefferson st.
'      Item: Riverside
'      Item: NJ
'      Item: 08075
'    Line #2
'      Item: Jack
'      Item: McGinnis
'      Item: 220 hobo Av.
'      Item: Phila
'      Item: PA
'      Item: 09119
'    Line #3
'      Item: Jennifer "Da Man"
'      Item: Repici
'      Item: 120 Jefferson St.
'      Item: Riverside
'      Item: NJ
'      Item: 08075
'    Line #4
'      Item: Stephen
'      Item: Tyler
'      Item: 7452 Terrace "At the Plaza" road
'      Item: SomeTown
'      Item: SD
'      Item: 91234
'    Line #5
'      Item: 
'      Item: Blankman
'      Item: 
'      Item: SomeTown
'      Item: SD
'      Item: 00298
'    Line #6
'      Item: Joan "the bone", Anne
'      Item: Jet
'      Item: 9th, at Terrace plc
'      Item: Desert City
'      Item: CO
'      Item: 00123
			
				
					
				
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						' Parse CSV File
 
' Read file into byte array
Dim fileBytes As Byte()
 
' Parse the contents of the file into a list
Dim fileContents = Utils.ParseCsv(fileBytes)
 
' Display the contents of the file
For lineIndex = 0 To fileContents.Count - 1
    Dim line = fileContents(lineIndex)
 
    Debug.Print($"Line #{lineIndex + 1}")
    For Each item In line
        Debug.Print($"  Item: {item}")
    Next
Next
 
' expected output:
'    Line #1
'      Item: Kenneth
'      Item: Perkins
'      Item: 120 jefferson st.
'      Item: Riverside
'      Item: NJ
'      Item: 08075
'    Line #2
'      Item: Jack
'      Item: McGinnis
'      Item: 220 hobo Av.
'      Item: Phila
'      Item: PA
'      Item: 09119
'    Line #3
'      Item: Jennifer "Da Man"
'      Item: Repici
'      Item: 120 Jefferson St.
'      Item: Riverside
'      Item: NJ
'      Item: 08075
'    Line #4
'      Item: Stephen
'      Item: Tyler
'      Item: 7452 Terrace "At the Plaza" road
'      Item: SomeTown
'      Item: SD
'      Item: 91234
'    Line #5
'      Item: 
'      Item: Blankman
'      Item: 
'      Item: SomeTown
'      Item: SD
'      Item: 00298
'    Line #6
'      Item: Joan "the bone", Anne
'      Item: Jet
'      Item: 9th, at Terrace plc
'      Item: Desert City
'      Item: CO
'      Item: 00123

2. Utils Namespace

The following is the Utils Namespace. Include this in your project to start using!



		
		
			Utils Namespace
			
Visual Basic .NET
			
			' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Dec 2, 2020
'    Taken From: http://programmingnotes.org/
'    File: Utils.vb
'    Description: Handles general utility functions
' ============================================================================
Option Strict On
Option Explicit On

Namespace Global.Utils
    Public Module modUtils
        ''' <summary>
        ''' Parses a Csv file and returns its results as a List. 
        ''' Each List index represents a line in the Csv file, with each 
        ''' item in the list representing a record contained on that line.
        ''' </summary>
        ''' <param name="fileBytes">The Csv file as a byte array</param> 
        ''' <param name="delimiters">The Csv data delimiter</param> 
        ''' <returns>The file contents as a List</returns>
        Public Function ParseCsv(fileBytes As Byte() _
                , Optional delimiters As String = ",") As List(Of List(Of String))
            Dim results = New List(Of List(Of String))
            Using stream = New System.IO.MemoryStream(fileBytes)
                Using parser = New Microsoft.VisualBasic.FileIO.TextFieldParser(stream)
                    parser.TextFieldType = Microsoft.VisualBasic.FileIO.FieldType.Delimited
                    parser.Delimiters = delimiters.Select(Function(letter) letter.ToString).ToArray
                    parser.HasFieldsEnclosedInQuotes = True

                    ' Parse each line in the file
                    While Not parser.EndOfData
                        Dim currentLine = parser.ReadFields
                        results.Add(currentLine.ToList)
                    End While
                End Using
            End Using
            Return results
        End Function
    End Module
End Namespace ' http://programmingnotes.org/
			
				
					
				
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						' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Dec 2, 2020
'    Taken From: http://programmingnotes.org/
'    File: Utils.vb
'    Description: Handles general utility functions
' ============================================================================
Option Strict On
Option Explicit On
 
Namespace Global.Utils
    Public Module modUtils
        ''' <summary>
        ''' Parses a Csv file and returns its results as a List. 
        ''' Each List index represents a line in the Csv file, with each 
        ''' item in the list representing a record contained on that line.
        ''' </summary>
        ''' <param name="fileBytes">The Csv file as a byte array</param> 
        ''' <param name="delimiters">The Csv data delimiter</param> 
        ''' <returns>The file contents as a List</returns>
        Public Function ParseCsv(fileBytes As Byte() _
                , Optional delimiters As String = ",") As List(Of List(Of String))
            Dim results = New List(Of List(Of String))
            Using stream = New System.IO.MemoryStream(fileBytes)
                Using parser = New Microsoft.VisualBasic.FileIO.TextFieldParser(stream)
                    parser.TextFieldType = Microsoft.VisualBasic.FileIO.FieldType.Delimited
                    parser.Delimiters = delimiters.Select(Function(letter) letter.ToString).ToArray
                    parser.HasFieldsEnclosedInQuotes = True
 
                    ' Parse each line in the file
                    While Not parser.EndOfData
                        Dim currentLine = parser.ReadFields
                        results.Add(currentLine.ToList)
                    End While
                End Using
            End Using
            Return results
        End Function
    End Module
End Namespace ' http://programmingnotes.org/

3. More Examples

Below are more examples demonstrating the use of the ‘Utils‘ Namespace. Don’t forget to include the module when running the examples!



		
		
			More Examples
			
Visual Basic .NET
			
			' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Dec 2, 2020
'    Taken From: http://programmingnotes.org/
'    File: Program.vb
'    Description: The following demonstrates the use of the Utils Namespace
' ============================================================================
Option Strict On
Option Explicit On
Imports System

Public Module Program
    Sub Main(args As String())
        Try
            ' Read file into byte array
            Dim fileBytes As Byte()

            ' Parse the contents of the file into a list
            Dim fileContents = Utils.ParseCsv(fileBytes)

            ' Display the contents of the file
            For lineIndex = 0 To fileContents.Count - 1
                Dim line = fileContents(lineIndex)

                Display($"Line #{lineIndex + 1}")
                For Each item In line
                    Display($"  Item: {item}")
                Next
            Next
        Catch ex As Exception
            Display(ex.ToString)
        Finally
            Console.ReadLine()
        End Try
    End Sub

    Public Sub Display(message As String)
        Console.WriteLine(message)
        Debug.Print(message)
    End Sub
End Module ' http://programmingnotes.org/
			
				
					
				
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						' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Dec 2, 2020
'    Taken From: http://programmingnotes.org/
'    File: Program.vb
'    Description: The following demonstrates the use of the Utils Namespace
' ============================================================================
Option Strict On
Option Explicit On
Imports System
 
Public Module Program
    Sub Main(args As String())
        Try
            ' Read file into byte array
            Dim fileBytes As Byte()
 
            ' Parse the contents of the file into a list
            Dim fileContents = Utils.ParseCsv(fileBytes)
 
            ' Display the contents of the file
            For lineIndex = 0 To fileContents.Count - 1
                Dim line = fileContents(lineIndex)
 
                Display($"Line #{lineIndex + 1}")
                For Each item In line
                    Display($"  Item: {item}")
                Next
            Next
        Catch ex As Exception
            Display(ex.ToString)
        Finally
            Console.ReadLine()
        End Try
    End Sub
 
    Public Sub Display(message As String)
        Console.WriteLine(message)
        Debug.Print(message)
    End Sub
End Module ' http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

VB.NET || How To Round A Number To The Nearest X Using VB.NET

December 01, 2020 admin No comments

The following is a module with functions which demonstrates how to round a number to the nearest X using VB.NET.

This function has the ability to either round a number to the nearest amount, always round up, or always round down. For example, when dealing with money, this is good for rounding a dollar amount to the nearest 5 cents.

1. Round – Nearest

The example below demonstrates the use of ‘Utils.RoundAmount‘ to round a number to the nearest 5 cents.

The optional function parameter determines they type of rounding to perform.



		
		
			1. Round - Nearest
			
Visual Basic .NET
			
			' Round - Nearest

' Declare values to round
Dim values = New Decimal() {19.28D, 31.22D, 19.91D, 19.87D, 0.05D}

' Declare step amount
Dim stepAmount = 0.05D

' Round to nearest amount
For Each value In values
    Debug.Print($"Value: {value}, Rounded: {Utils.RoundAmount(value, stepAmount)}")
Next

' expected output:
'    Value: 19.28, Rounded: 19.3
'    Value: 31.22, Rounded: 31.2
'    Value: 19.91, Rounded: 19.9
'    Value: 19.87, Rounded: 19.85
'    Value: 0.05, Rounded: 0.05
			
				
					
				
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						' Round - Nearest
 
' Declare values to round
Dim values = New Decimal() {19.28D, 31.22D, 19.91D, 19.87D, 0.05D}
 
' Declare step amount
Dim stepAmount = 0.05D
 
' Round to nearest amount
For Each value In values
    Debug.Print($"Value: {value}, Rounded: {Utils.RoundAmount(value, stepAmount)}")
Next
 
' expected output:
'    Value: 19.28, Rounded: 19.3
'    Value: 31.22, Rounded: 31.2
'    Value: 19.91, Rounded: 19.9
'    Value: 19.87, Rounded: 19.85
'    Value: 0.05, Rounded: 0.05

2. Round – Up

The example below demonstrates the use of ‘Utils.RoundAmount‘ to always round a number up to the nearest 5 cents.

The optional function parameter determines they type of rounding to perform.



		
		
			2. Round - Up
			
Visual Basic .NET
			
			' Round - Up

' Declare values to round
Dim values = New Decimal() {19.28D, 31.22D, 19.91D, 19.87D, 0.05D}

' Declare step amount
Dim stepAmount = 0.05D

' Round up to nearest amount
For Each value In values
    Debug.Print($"Value: {value}, Rounded: {Utils.RoundAmount(value, stepAmount, Utils.RoundType.Up)}")
Next

' expected output:
'    Value: 19.28, Rounded: 19.3
'    Value: 31.22, Rounded: 31.25
'    Value: 19.91, Rounded: 19.95
'    Value: 19.87, Rounded: 19.9
'    Value: 0.05, Rounded: 0.05
			
				
					
				
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						' Round - Up
 
' Declare values to round
Dim values = New Decimal() {19.28D, 31.22D, 19.91D, 19.87D, 0.05D}
 
' Declare step amount
Dim stepAmount = 0.05D
 
' Round up to nearest amount
For Each value In values
    Debug.Print($"Value: {value}, Rounded: {Utils.RoundAmount(value, stepAmount, Utils.RoundType.Up)}")
Next
 
' expected output:
'    Value: 19.28, Rounded: 19.3
'    Value: 31.22, Rounded: 31.25
'    Value: 19.91, Rounded: 19.95
'    Value: 19.87, Rounded: 19.9
'    Value: 0.05, Rounded: 0.05

3. Round – Down

The example below demonstrates the use of ‘Utils.RoundAmount‘ to always round a number down to the nearest 5 cents.

The optional function parameter determines they type of rounding to perform.



		
		
			3. Round - Down
			
Visual Basic .NET
			
			' Round - Down 

' Declare values to round
Dim values = New Decimal() {19.28D, 31.22D, 19.91D, 19.87D, 0.05D}

' Declare step amount
Dim stepAmount = 0.05D

' Round down to nearest amount
For Each value In values
    Debug.Print($"Value: {value}, Rounded: {Utils.RoundAmount(value, stepAmount, Utils.RoundType.Down)}")
Next

' expected output:
'    Value: 19.28, Rounded: 19.25
'    Value: 31.22, Rounded: 31.2
'    Value: 19.91, Rounded: 19.9
'    Value: 19.87, Rounded: 19.85
'    Value: 0.05, Rounded: 0.05
			
				
					
				
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						' Round - Down 
 
' Declare values to round
Dim values = New Decimal() {19.28D, 31.22D, 19.91D, 19.87D, 0.05D}
 
' Declare step amount
Dim stepAmount = 0.05D
 
' Round down to nearest amount
For Each value In values
    Debug.Print($"Value: {value}, Rounded: {Utils.RoundAmount(value, stepAmount, Utils.RoundType.Down)}")
Next
 
' expected output:
'    Value: 19.28, Rounded: 19.25
'    Value: 31.22, Rounded: 31.2
'    Value: 19.91, Rounded: 19.9
'    Value: 19.87, Rounded: 19.85
'    Value: 0.05, Rounded: 0.05

4. Utils Namespace

The following is the Utils Namespace. Include this in your project to start using!



		
		
			Utils Namespace
			
Visual Basic .NET
			
			' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Dec 1, 2020
'    Taken From: http://programmingnotes.org/
'    File: Utils.vb
'    Description: Handles general utility functions
' ============================================================================
Option Strict On
Option Explicit On

Namespace Global.Utils
    Public Module modUtils
        Public Enum RoundType
            Nearest
            Up
            Down
        End Enum

        ''' <summary>
        ''' Rounds a number to the nearest X
        ''' </summary>
        ''' <param name="value">The value to round</param> 
        ''' <param name="stepAmount">The amount to round the value by</param>
        ''' <param name="type">The type of rounding to perform</param>
        ''' <returns>The value rounded by the step amount and type</returns>
        Public Function RoundAmount(value As Decimal, stepAmount As Decimal _
                    , Optional type As RoundType = RoundType.Nearest) As Decimal
            Dim inverse = 1 / stepAmount
            Dim dividend = value * inverse
            Select Case type
                Case RoundType.Nearest
                    dividend = Math.Round(dividend)
                Case RoundType.Up
                    dividend = Math.Ceiling(dividend)
                Case RoundType.Down
                    dividend = Math.Floor(dividend)
                Case Else
                    Throw New ArgumentException($"Unknown type: {type}", NameOf(type))
            End Select
            Dim result = dividend / inverse
            Return result
        End Function
    End Module
End Namespace ' http://programmingnotes.org/
			
				
					
				
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						' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Dec 1, 2020
'    Taken From: http://programmingnotes.org/
'    File: Utils.vb
'    Description: Handles general utility functions
' ============================================================================
Option Strict On
Option Explicit On
 
Namespace Global.Utils
    Public Module modUtils
        Public Enum RoundType
            Nearest
            Up
            Down
        End Enum
 
        ''' <summary>
        ''' Rounds a number to the nearest X
        ''' </summary>
        ''' <param name="value">The value to round</param> 
        ''' <param name="stepAmount">The amount to round the value by</param>
        ''' <param name="type">The type of rounding to perform</param>
        ''' <returns>The value rounded by the step amount and type</returns>
        Public Function RoundAmount(value As Decimal, stepAmount As Decimal _
                    , Optional type As RoundType = RoundType.Nearest) As Decimal
            Dim inverse = 1 / stepAmount
            Dim dividend = value * inverse
            Select Case type
                Case RoundType.Nearest
                    dividend = Math.Round(dividend)
                Case RoundType.Up
                    dividend = Math.Ceiling(dividend)
                Case RoundType.Down
                    dividend = Math.Floor(dividend)
                Case Else
                    Throw New ArgumentException($"Unknown type: {type}", NameOf(type))
            End Select
            Dim result = dividend / inverse
            Return result
        End Function
    End Module
End Namespace ' http://programmingnotes.org/

5. More Examples

Below are more examples demonstrating the use of the ‘Utils‘ Namespace. Don’t forget to include the module when running the examples!



		
		
			More Examples
			
Visual Basic .NET
			
			' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Dec 1, 2020
'    Taken From: http://programmingnotes.org/
'    File: Program.vb
'    Description: The following demonstrates the use of the Utils Namespace
' ============================================================================
Option Strict On
Option Explicit On
Imports System

Public Module Program
    Sub Main(args As String())
        Try
            ' Declare values to round
            Dim values = New Decimal() {19.28D, 31.22D, 19.91D, 19.87D, 0.05D}

            ' Declare step amount
            Dim stepAmount = 0.05D

            ' Round to nearest amount
            For Each value In values
                Display($"Value: {value}, Rounded: {Utils.RoundAmount(value, stepAmount)}")
            Next

            Display("")

            ' Round up to nearest amount
            For Each value In values
                Display($"Value: {value}, Rounded: {Utils.RoundAmount(value, stepAmount, Utils.RoundType.Up)}")
            Next

            Display("")

            ' Round down to nearest amount
            For Each value In values
                Display($"Value: {value}, Rounded: {Utils.RoundAmount(value, stepAmount, Utils.RoundType.Down)}")
            Next
        Catch ex As Exception
            Display(ex.ToString)
        Finally
            Console.ReadLine()
        End Try
    End Sub

    Public Sub Display(message As String)
        Console.WriteLine(message)
        Debug.Print(message)
    End Sub
End Module ' http://programmingnotes.org/
			
				
					
				
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						' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Dec 1, 2020
'    Taken From: http://programmingnotes.org/
'    File: Program.vb
'    Description: The following demonstrates the use of the Utils Namespace
' ============================================================================
Option Strict On
Option Explicit On
Imports System
 
Public Module Program
    Sub Main(args As String())
        Try
            ' Declare values to round
            Dim values = New Decimal() {19.28D, 31.22D, 19.91D, 19.87D, 0.05D}
 
            ' Declare step amount
            Dim stepAmount = 0.05D
 
            ' Round to nearest amount
            For Each value In values
                Display($"Value: {value}, Rounded: {Utils.RoundAmount(value, stepAmount)}")
            Next
 
            Display("")
 
            ' Round up to nearest amount
            For Each value In values
                Display($"Value: {value}, Rounded: {Utils.RoundAmount(value, stepAmount, Utils.RoundType.Up)}")
            Next
 
            Display("")
 
            ' Round down to nearest amount
            For Each value In values
                Display($"Value: {value}, Rounded: {Utils.RoundAmount(value, stepAmount, Utils.RoundType.Down)}")
            Next
        Catch ex As Exception
            Display(ex.ToString)
        Finally
            Console.ReadLine()
        End Try
    End Sub
 
    Public Sub Display(message As String)
        Console.WriteLine(message)
        Debug.Print(message)
    End Sub
End Module ' http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

VB.NET || How To Replace A Letter With Its Alphabet Position Using VB.NET

November 30, 2020 admin No comments

The following is a module with functions which demonstrates how to replace a letter with its alphabet position using VB.NET.

1. Replace With Alphabet Position

The example below demonstrates the use of ‘Utils.GetAlphabetPosition‘ to replace a letter with its alphabet position.



		
		
			1. Replace With Alphabet Position
			
Visual Basic .NET
			
			' Replace With Alphabet Position

' Get alphabet position
Dim result = Utils.GetAlphabetPosition("The sunset sets at twelve o' clock.")

' Display the results
Debug.Print(String.Join(" ", result))

' expected output:
'    20 8 5 19 21 14 19 5 20 19 5 20 19 1 20 20 23 5 12 22 5 15 3 12 15 3 11
			
				
					
				
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						' Replace With Alphabet Position
 
' Get alphabet position
Dim result = Utils.GetAlphabetPosition("The sunset sets at twelve o' clock.")
 
' Display the results
Debug.Print(String.Join(" ", result))
 
' expected output:
'    20 8 5 19 21 14 19 5 20 19 5 20 19 1 20 20 23 5 12 22 5 15 3 12 15 3 11

2. Utils Namespace

The following is the Utils Namespace. Include this in your project to start using!



		
		
			Utils Namespace
			
Visual Basic .NET
			
			' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Nov 30, 2020
'    Taken From: http://programmingnotes.org/
'    File: Utils.vb
'    Description: Handles general utility functions
' ============================================================================
Option Strict On
Option Explicit On

Namespace Global.Utils
    Public Module modUtils
        ''' <summary>
        ''' Gets the alphabet position of each character in a string
        ''' </summary>
        ''' <param name="text">The text to get the position</param> 
        ''' <returns>The alphabet position of each character</returns>
        Public Function GetAlphabetPosition(text As String) As List(Of Integer)
            Dim alphabet = "abcdefghijklmnopqrstuvwxyz"
            Dim result = New List(Of Integer)
            For Each letter In text.ToLower
                Dim index = alphabet.IndexOf(letter)
                If index > -1 Then
                    result.Add(index + 1)
                End If
            Next
            Return result
        End Function
    End Module
End Namespace ' http://programmingnotes.org/
			
				
					
				
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						' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Nov 30, 2020
'    Taken From: http://programmingnotes.org/
'    File: Utils.vb
'    Description: Handles general utility functions
' ============================================================================
Option Strict On
Option Explicit On
 
Namespace Global.Utils
    Public Module modUtils
        ''' <summary>
        ''' Gets the alphabet position of each character in a string
        ''' </summary>
        ''' <param name="text">The text to get the position</param> 
        ''' <returns>The alphabet position of each character</returns>
        Public Function GetAlphabetPosition(text As String) As List(Of Integer)
            Dim alphabet = "abcdefghijklmnopqrstuvwxyz"
            Dim result = New List(Of Integer)
            For Each letter In text.ToLower
                Dim index = alphabet.IndexOf(letter)
                If index > -1 Then
                    result.Add(index + 1)
                End If
            Next
            Return result
        End Function
    End Module
End Namespace ' http://programmingnotes.org/

3. More Examples

Below are more examples demonstrating the use of the ‘Utils‘ Namespace. Don’t forget to include the module when running the examples!



		
		
			More Examples
			
Visual Basic .NET
			
			' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Nov 30, 2020
'    Taken From: http://programmingnotes.org/
'    File: Program.vb
'    Description: The following demonstrates the use of the Utils Namespace
' ============================================================================
Option Strict On
Option Explicit On
Imports System

Public Module Program
    Sub Main(args As String())
        Try
            Dim result = Utils.GetAlphabetPosition("The sunset sets at twelve o' clock.")

            Display(String.Join(" ", result))
        Catch ex As Exception
            Display(ex.ToString)
        Finally
            Console.ReadLine()
        End Try
    End Sub

    Public Sub Display(message As String)
        Console.WriteLine(message)
        Debug.Print(message)
    End Sub
End Module ' http://programmingnotes.org/
			
				
					
				
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						' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Nov 30, 2020
'    Taken From: http://programmingnotes.org/
'    File: Program.vb
'    Description: The following demonstrates the use of the Utils Namespace
' ============================================================================
Option Strict On
Option Explicit On
Imports System
 
Public Module Program
    Sub Main(args As String())
        Try
            Dim result = Utils.GetAlphabetPosition("The sunset sets at twelve o' clock.")
 
            Display(String.Join(" ", result))
        Catch ex As Exception
            Display(ex.ToString)
        Finally
            Console.ReadLine()
        End Try
    End Sub
 
    Public Sub Display(message As String)
        Console.WriteLine(message)
        Debug.Print(message)
    End Sub
End Module ' http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

VB.NET || How To Generate A Random String Of A Specified Length Using VB.NET

November 30, 2020 admin No comments

The following is a module with functions which demonstrates how to generate a random code of a specified length using VB.NET.

The function demonstrated on this page has the ability to generate random strings that contains only letters, only numerical digits, or alphanumeric strings.

1. Random Code – Alphabetical

The example below demonstrates the use of ‘Utils.GetRandomCode‘ to generate a code of a specified length that contains only letters.

The optional function parameter determines the type of code that is generated.



		
		
			1. Random Code - Alphabetical
			
Visual Basic .NET
			
			' Random Code - Alphabetical

' Generate code containing only letters
Dim letters = Utils.GetRandomCode(5)

' Display the code
Debug.Print($"Code: {letters}")

' example output:
'    Code: DWhxO
			
				
					
				
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						' Random Code - Alphabetical
 
' Generate code containing only letters
Dim letters = Utils.GetRandomCode(5)
 
' Display the code
Debug.Print($"Code: {letters}")
 
' example output:
'    Code: DWhxO

2. Random Code – Numeric

The example below demonstrates the use of ‘Utils.GetRandomCode‘ to generate a code of a specified length that contains only digits.

The optional function parameter determines the type of code that is generated.



		
		
			2. Random Code - Numeric
			
Visual Basic .NET
			
			' Random Code - Numeric

' Generate code containing only digits
Dim numeric = Utils.GetRandomCode(7, Utils.CodeType.Numeric)

' Display the code
Debug.Print($"Code: {numeric}")

' example output:
'    Code: 6407422
			
				
					
				
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						' Random Code - Numeric
 
' Generate code containing only digits
Dim numeric = Utils.GetRandomCode(7, Utils.CodeType.Numeric)
 
' Display the code
Debug.Print($"Code: {numeric}")
 
' example output:
'    Code: 6407422

3. Random Code – Alphanumeric

The example below demonstrates the use of ‘Utils.GetRandomCode‘ to generate a code of a specified length that is alphanumeric.

The optional function parameter determines the type of code that is generated.



		
		
			3. Random Code - Alphanumeric
			
Visual Basic .NET
			
			' Random Code - Alphanumeric 

' Generate alphanumeric code
Dim alphaNumeric = Utils.GetRandomCode(10, Utils.CodeType.AlphaNumeric)

' Display the code
Debug.Print($"Code: {alphaNumeric}")

' example output:
'    Code: C3G9mt9wf8
			
				
					
				
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						' Random Code - Alphanumeric 
 
' Generate alphanumeric code
Dim alphaNumeric = Utils.GetRandomCode(10, Utils.CodeType.AlphaNumeric)
 
' Display the code
Debug.Print($"Code: {alphaNumeric}")
 
' example output:
'    Code: C3G9mt9wf8

4. Utils Namespace

The following is the Utils Namespace. Include this in your project to start using!



		
		
			Utils Namespace
			
Visual Basic .NET
			
			' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Nov 30, 2020
'    Taken From: http://programmingnotes.org/
'    File: Utils.vb
'    Description: Handles general utility functions
' ============================================================================
Option Strict On
Option Explicit On

Namespace Global.Utils
    Public Module modUtils
        Public Enum CodeType
            ''' <summary>
            ''' Code contains only letters
            ''' </summary>
            Alphabetical
            ''' <summary>
            ''' Code contains only digits
            ''' </summary>
            Numeric
            ''' <summary>
            ''' Code contains letters and digits
            ''' </summary>
            AlphaNumeric
        End Enum

        ''' <summary>
        ''' Generates a random string of a specified length according to the type
        ''' </summary>
        ''' <param name="length">The length of the random string</param> 
        ''' <param name="type">The type of string to generate</param>
        ''' <returns>The random string according to the type</returns>
        Public Function GetRandomCode(length As Integer _
                , Optional type As CodeType = CodeType.Alphabetical) As String
            Dim digits = "0123456789"
            Dim alphabet = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
            Dim source = String.Empty

            Select Case type
                Case CodeType.Alphabetical
                    source = alphabet
                Case CodeType.Numeric
                    source = digits
                Case CodeType.AlphaNumeric
                    source = alphabet + digits
                Case Else
                    Throw New ArgumentException($"Unknown type: {type}", NameOf(type))
            End Select

            Dim r = New Random
            Dim result = New System.Text.StringBuilder
            While result.Length < length
                result.Append(source(r.Next(0, source.Length)))
            End While

            Return result.ToString
        End Function
    End Module
End Namespace ' http://programmingnotes.org/
			
				
					
				
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						' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Nov 30, 2020
'    Taken From: http://programmingnotes.org/
'    File: Utils.vb
'    Description: Handles general utility functions
' ============================================================================
Option Strict On
Option Explicit On
 
Namespace Global.Utils
    Public Module modUtils
        Public Enum CodeType
            ''' <summary>
            ''' Code contains only letters
            ''' </summary>
            Alphabetical
            ''' <summary>
            ''' Code contains only digits
            ''' </summary>
            Numeric
            ''' <summary>
            ''' Code contains letters and digits
            ''' </summary>
            AlphaNumeric
        End Enum
 
        ''' <summary>
        ''' Generates a random string of a specified length according to the type
        ''' </summary>
        ''' <param name="length">The length of the random string</param> 
        ''' <param name="type">The type of string to generate</param>
        ''' <returns>The random string according to the type</returns>
        Public Function GetRandomCode(length As Integer _
                , Optional type As CodeType = CodeType.Alphabetical) As String
            Dim digits = "0123456789"
            Dim alphabet = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
            Dim source = String.Empty
 
            Select Case type
                Case CodeType.Alphabetical
                    source = alphabet
                Case CodeType.Numeric
                    source = digits
                Case CodeType.AlphaNumeric
                    source = alphabet + digits
                Case Else
                    Throw New ArgumentException($"Unknown type: {type}", NameOf(type))
            End Select
 
            Dim r = New Random
            Dim result = New System.Text.StringBuilder
            While result.Length < length
                result.Append(source(r.Next(0, source.Length)))
            End While
 
            Return result.ToString
        End Function
    End Module
End Namespace ' http://programmingnotes.org/

5. More Examples

Below are more examples demonstrating the use of the ‘Utils‘ Namespace. Don’t forget to include the module when running the examples!



		
		
			More Examples
			
Visual Basic .NET
			
			' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Nov 30, 2020
'    Taken From: http://programmingnotes.org/
'    File: Program.vb
'    Description: The following demonstrates the use of the Utils Namespace
' ============================================================================
Option Strict On
Option Explicit On
Imports System

Public Module Program
    Sub Main(args As String())
        Try
            ' Generate code containing only letters
            Dim letters = Utils.GetRandomCode(5)

            ' Display the code
            Display($"Code: {letters}")

            Display("")

            ' Generate code containing only digits
            Dim numeric = Utils.GetRandomCode(7, Utils.CodeType.Numeric)

            ' Display the code
            Display($"Code: {numeric}")

            Display("")

            ' Generate alphanumeric code
            Dim alphaNumeric = Utils.GetRandomCode(10, Utils.CodeType.AlphaNumeric)

            ' Display the code
            Display($"Code: {alphaNumeric}")
        Catch ex As Exception
            Display(ex.ToString)
        Finally
            Console.ReadLine()
        End Try
    End Sub

    Public Sub Display(message As String)
        Console.WriteLine(message)
        Debug.Print(message)
    End Sub
End Module ' http://programmingnotes.org/
			
				
					
				
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						' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Nov 30, 2020
'    Taken From: http://programmingnotes.org/
'    File: Program.vb
'    Description: The following demonstrates the use of the Utils Namespace
' ============================================================================
Option Strict On
Option Explicit On
Imports System
 
Public Module Program
    Sub Main(args As String())
        Try
            ' Generate code containing only letters
            Dim letters = Utils.GetRandomCode(5)
 
            ' Display the code
            Display($"Code: {letters}")
 
            Display("")
 
            ' Generate code containing only digits
            Dim numeric = Utils.GetRandomCode(7, Utils.CodeType.Numeric)
 
            ' Display the code
            Display($"Code: {numeric}")
 
            Display("")
 
            ' Generate alphanumeric code
            Dim alphaNumeric = Utils.GetRandomCode(10, Utils.CodeType.AlphaNumeric)
 
            ' Display the code
            Display($"Code: {alphaNumeric}")
        Catch ex As Exception
            Display(ex.ToString)
        Finally
            Console.ReadLine()
        End Try
    End Sub
 
    Public Sub Display(message As String)
        Console.WriteLine(message)
        Debug.Print(message)
    End Sub
End Module ' http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

VB.NET || How To Get A List Of Files At A Given Path Directory Using VB.NET

November 30, 2020 admin No comments

The following is a module with functions which demonstrates how to get a list of files at a given directory path using VB.NET.

The function demonstrated on this page returns a list of System.IO.FileInfo, which contains information about the files in the given directory.

1. Get Files In Directory

The example below demonstrates the use of ‘Utils.GetFilesInDirectory‘ to get a list of files at a given path directory.

The optional function parameter lets you specify the search option. This lets you specify whether to limit the search to just the current directory, or expand the search to the current directory and all subdirectories when searching for files.



		
		
			1. Get Files In Directory
			
Visual Basic .NET
			
			' Get Files In Directory

' Declare directory path
Dim directory = "C:\Users\Name\Desktop"

' Get files at the specified directory
Dim files = Utils.GetFilesInDirectory(directory)

' Display info about the files
For Each file In files
    Debug.Print($"File: {file.FullName} - Last Modified: {file.LastWriteTime}")
Next

' example output:
'    File: C:\Users\Name\Desktop\text.txt - Last Modified: 10/7/2020 12:47:56 PM
'    File: C:\Users\Name\Desktop\image.png - Last Modified: 9/4/2020 8:36:25 PM
'    File: C:\Users\Name\Desktop\document.docx - Last Modified: 3/7/2018 9:26:19 PM
			
				
					
				
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						' Get Files In Directory
 
' Declare directory path
Dim directory = "C:\Users\Name\Desktop"
 
' Get files at the specified directory
Dim files = Utils.GetFilesInDirectory(directory)
 
' Display info about the files
For Each file In files
    Debug.Print($"File: {file.FullName} - Last Modified: {file.LastWriteTime}")
Next
 
' example output:
'    File: C:\Users\Name\Desktop\text.txt - Last Modified: 10/7/2020 12:47:56 PM
'    File: C:\Users\Name\Desktop\image.png - Last Modified: 9/4/2020 8:36:25 PM
'    File: C:\Users\Name\Desktop\document.docx - Last Modified: 3/7/2018 9:26:19 PM

2. Utils Namespace

The following is the Utils Namespace. Include this in your project to start using!



		
		
			Utils Namespace
			
Visual Basic .NET
			
			' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Nov 30, 2020
'    Taken From: http://programmingnotes.org/
'    File: Utils.vb
'    Description: Handles general utility functions
' ============================================================================
Option Strict On
Option Explicit On

Namespace Global.Utils
    Public Module modUtils
        ''' <summary>
        ''' Returns a list of <see cref="System.IO.FileInfo"/> of the files 
        ''' in the given directory
        ''' </summary>
        ''' <param name="directory">The relative or absolute path to the directory to search</param> 
        ''' <param name="searchOption">The file search option</param>
        ''' <returns>A list of <see cref="System.IO.FileInfo"/> in the given directory</returns>
        Public Function GetFilesInDirectory(directory As String _
                , Optional searchOption As System.IO.SearchOption = System.IO.SearchOption.TopDirectoryOnly) As List(Of System.IO.FileInfo)
            Return System.IO.Directory.GetFiles(directory, "*", searchOption) _
                .Select(Function(fileName) New System.IO.FileInfo(fileName)).ToList
        End Function
    End Module
End Namespace ' http://programmingnotes.org/
			
				
					
				
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						' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Nov 30, 2020
'    Taken From: http://programmingnotes.org/
'    File: Utils.vb
'    Description: Handles general utility functions
' ============================================================================
Option Strict On
Option Explicit On
 
Namespace Global.Utils
    Public Module modUtils
        ''' <summary>
        ''' Returns a list of <see cref="System.IO.FileInfo"/> of the files 
        ''' in the given directory
        ''' </summary>
        ''' <param name="directory">The relative or absolute path to the directory to search</param> 
        ''' <param name="searchOption">The file search option</param>
        ''' <returns>A list of <see cref="System.IO.FileInfo"/> in the given directory</returns>
        Public Function GetFilesInDirectory(directory As String _
                , Optional searchOption As System.IO.SearchOption = System.IO.SearchOption.TopDirectoryOnly) As List(Of System.IO.FileInfo)
            Return System.IO.Directory.GetFiles(directory, "*", searchOption) _
                .Select(Function(fileName) New System.IO.FileInfo(fileName)).ToList
        End Function
    End Module
End Namespace ' http://programmingnotes.org/

3. More Examples

Below are more examples demonstrating the use of the ‘Utils‘ Namespace. Don’t forget to include the module when running the examples!



		
		
			More Examples
			
Visual Basic .NET
			
			' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Nov 30, 2020
'    Taken From: http://programmingnotes.org/
'    File: Program.vb
'    Description: The following demonstrates the use of the Utils Namespace
' ============================================================================
Option Strict On
Option Explicit On
Imports System

Public Module Program
    Sub Main(args As String())
        Try
            ' Declare directory path
            Dim directory = "C:\path\to\directory"

            ' Get files at the specified directory
            Dim files = Utils.GetFilesInDirectory(directory)

            ' Display info about the files
            For Each file In files
                Display($"File: {file.FullName} - Last Modified: {file.LastWriteTime}")
            Next
        Catch ex As Exception
            Display(ex.ToString)
        Finally
            Console.ReadLine()
        End Try
    End Sub

    Public Sub Display(message As String)
        Console.WriteLine(message)
        Debug.Print(message)
    End Sub
End Module ' http://programmingnotes.org/
			
				
					
				
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						' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Nov 30, 2020
'    Taken From: http://programmingnotes.org/
'    File: Program.vb
'    Description: The following demonstrates the use of the Utils Namespace
' ============================================================================
Option Strict On
Option Explicit On
Imports System
 
Public Module Program
    Sub Main(args As String())
        Try
            ' Declare directory path
            Dim directory = "C:\path\to\directory"
 
            ' Get files at the specified directory
            Dim files = Utils.GetFilesInDirectory(directory)
 
            ' Display info about the files
            For Each file In files
                Display($"File: {file.FullName} - Last Modified: {file.LastWriteTime}")
            Next
        Catch ex As Exception
            Display(ex.ToString)
        Finally
            Console.ReadLine()
        End Try
    End Sub
 
    Public Sub Display(message As String)
        Console.WriteLine(message)
        Debug.Print(message)
    End Sub
End Module ' http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

VB.NET || How To Get The Computer & User Client IP Address Using VB.NET

November 29, 2020 admin No comments

The following is a module with functions which demonstrates how to get the computers and user client request IPv4 IP address using VB.NET.

The function demonstrated on this page returns the IPv4 address of the calling user. When under a web environment, it returns the clients System.Web.HttpContext.Current.Request IP address, otherwise it returns the IP address of the local machine (i.e: server) if there is no request.

The following function uses System.Web to determine the IP address of the client.

Note: To use the function in this module, make sure you have a reference to ‘System.Web‘ in your project.

One way to do this is, in your Solution Explorer (where all the files are shown with your project), right click the ‘References‘ folder, click ‘Add Reference‘, then type ‘System.Web‘ in the search box, and add the reference titled System.Web in the results Tab.

1. Get IP Address

The example below demonstrates the use of ‘Utils.GetIPv4Address‘ to get the IPv4 address of the calling user.



		
		
			1. Get IP Address
			
Visual Basic .NET
			
			' Get IP Address

' Get IP address of the current user
Dim ipAddress = Utils.GetIPv4Address

Debug.Print($"IP Address: {ipAddress}")

' example output:
'    IP Address: 192.168.0.5 
			
				
					
				
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						' Get IP Address
 
' Get IP address of the current user
Dim ipAddress = Utils.GetIPv4Address
 
Debug.Print($"IP Address: {ipAddress}")
 
' example output:
'    IP Address: 192.168.0.5

2. Utils Namespace

The following is the Utils Namespace. Include this in your project to start using!



		
		
			Utils Namespace
			
Visual Basic .NET
			
			' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Nov 29, 2020
'    Taken From: http://programmingnotes.org/
'    File: Utils.vb
'    Description: Handles general utility functions
' ============================================================================
Option Strict On
Option Explicit On

Namespace Global.Utils
    Public Module modUtils
        ''' <summary>
        ''' Returns the IPv4 address of the calling user. When under a web 
        ''' environment, returns the <see cref="System.Web.HttpRequest"/> 
        ''' IP address, otherwise returns the IP address of the local machine
        ''' </summary>
        ''' <returns>The IPv4 address of the calling user</returns>
        Public Function GetIPv4Address() As String
            Dim ipAddress = String.Empty

            ' Get client ip address
            If System.Web.HttpContext.Current IsNot Nothing _
                AndAlso System.Web.HttpContext.Current.Request IsNot Nothing Then

                ' Get client ip address using ServerVariables
                Dim request = System.Web.HttpContext.Current.Request
                ipAddress = request.ServerVariables("HTTP_X_FORWARDED_FOR")
                If Not String.IsNullOrEmpty(ipAddress) Then
                    Dim addresses = ipAddress.Split(",".ToCharArray, StringSplitOptions.RemoveEmptyEntries)
                    If addresses.Length > 0 Then
                        ipAddress = addresses(0)
                    End If
                End If
                If String.IsNullOrEmpty(ipAddress) Then
                    ipAddress = request.ServerVariables("REMOTE_ADDR")
                End If

                ' Get client ip address using UserHostAddress
                If String.IsNullOrEmpty(ipAddress) Then
                    Dim clientIPA = GetNetworkAddress(request.UserHostAddress)
                    If clientIPA IsNot Nothing Then
                        ipAddress = clientIPA.ToString
                    End If
                End If
            End If

            ' Get local machine ip address
            If String.IsNullOrEmpty(ipAddress) Then
                Dim loacalIPA = GetNetworkAddress(System.Net.Dns.GetHostName)
                If loacalIPA IsNot Nothing Then
                    ipAddress = loacalIPA.ToString
                End If
            End If
            Return ipAddress
        End Function

        Private Function GetNetworkAddress(addresses As String) As System.Net.IPAddress
            Return System.Net.Dns.GetHostAddresses(addresses) _
                .FirstOrDefault(Function(x) x.AddressFamily = System.Net.Sockets.AddressFamily.InterNetwork)
        End Function
    End Module
End Namespace ' http://programmingnotes.org/
			
				
					
				
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						' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Nov 29, 2020
'    Taken From: http://programmingnotes.org/
'    File: Utils.vb
'    Description: Handles general utility functions
' ============================================================================
Option Strict On
Option Explicit On
 
Namespace Global.Utils
    Public Module modUtils
        ''' <summary>
        ''' Returns the IPv4 address of the calling user. When under a web 
        ''' environment, returns the <see cref="System.Web.HttpRequest"/> 
        ''' IP address, otherwise returns the IP address of the local machine
        ''' </summary>
        ''' <returns>The IPv4 address of the calling user</returns>
        Public Function GetIPv4Address() As String
            Dim ipAddress = String.Empty
 
            ' Get client ip address
            If System.Web.HttpContext.Current IsNot Nothing _
                AndAlso System.Web.HttpContext.Current.Request IsNot Nothing Then
 
                ' Get client ip address using ServerVariables
                Dim request = System.Web.HttpContext.Current.Request
                ipAddress = request.ServerVariables("HTTP_X_FORWARDED_FOR")
                If Not String.IsNullOrEmpty(ipAddress) Then
                    Dim addresses = ipAddress.Split(",".ToCharArray, StringSplitOptions.RemoveEmptyEntries)
                    If addresses.Length > 0 Then
                        ipAddress = addresses(0)
                    End If
                End If
                If String.IsNullOrEmpty(ipAddress) Then
                    ipAddress = request.ServerVariables("REMOTE_ADDR")
                End If
 
                ' Get client ip address using UserHostAddress
                If String.IsNullOrEmpty(ipAddress) Then
                    Dim clientIPA = GetNetworkAddress(request.UserHostAddress)
                    If clientIPA IsNot Nothing Then
                        ipAddress = clientIPA.ToString
                    End If
                End If
            End If
 
            ' Get local machine ip address
            If String.IsNullOrEmpty(ipAddress) Then
                Dim loacalIPA = GetNetworkAddress(System.Net.Dns.GetHostName)
                If loacalIPA IsNot Nothing Then
                    ipAddress = loacalIPA.ToString
                End If
            End If
            Return ipAddress
        End Function
 
        Private Function GetNetworkAddress(addresses As String) As System.Net.IPAddress
            Return System.Net.Dns.GetHostAddresses(addresses) _
                .FirstOrDefault(Function(x) x.AddressFamily = System.Net.Sockets.AddressFamily.InterNetwork)
        End Function
    End Module
End Namespace ' http://programmingnotes.org/

3. More Examples

Below are more examples demonstrating the use of the ‘Utils‘ Namespace. Don’t forget to include the module when running the examples!



		
		
			More Examples
			
Visual Basic .NET
			
			' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Nov 29, 2020
'    Taken From: http://programmingnotes.org/
'    File: Program.vb
'    Description: The following demonstrates the use of the Utils Namespace
' ============================================================================
Option Strict On
Option Explicit On
Imports System

Public Module Program
    Sub Main(args As String())
        Try
            ' Get IP address of the current user
            Dim ipAddress = Utils.GetIPv4Address

            Display($"IP Address: {ipAddress}")
        Catch ex As Exception
            Display(ex.ToString)
        Finally
            Console.ReadLine()
        End Try
    End Sub

    Public Sub Display(message As String)
        Console.WriteLine(message)
        Debug.Print(message)
    End Sub
End Module ' http://programmingnotes.org/
			
				
					
				
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