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.

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Posted in: Console, VB.NET Tags: string random code, vb.net

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

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