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.

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Posted in: Console, VB.NET Tags: csv file, vb.net

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

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