How to Parse a CSV File Using VB

The format CSV (comma separated values) is one of the most common for data files. A comma is used to delineate objects on each line of the file. Many applications, such as Excel, output data in this format. Programmers will load the data from a csv file into a code structure such as an array or table. Visual Basic 2008 provides features reducing the code required to parse (separate a large block of data into distinct items) a csv file.

Things You'll Need

• Text editor
• Microsoft Visual Basic Express Edition 2008
• CSV file

Instructions

1. We will create and parse a simple data file for purposes of illustration. Open the text editor and enter the following data:

   1,2,3,4,5,6
   A,B,C,D,E

2. Save this file to "c:\test.csv".

3. Open the Visual Basic application and create a new project using the "Ctrl" and "N" keys. Select the "Windows Forms Application" template.

4. Create a button labeled "Button1" on the form.

5. Double click on "Button1" and enter the following code:

   Using MyReader As New Microsoft.VisualBasic.FileIO.TextFieldParser _
   ("c:\test.csv")
   MyReader.TextFieldType = Microsoft.VisualBasic.FileIO.FieldType.Delimited
   'set the delimiter to any value
   MyReader.Delimiters = New String() {","}

   Dim currentRow As String()

   'Loop through all of the fields in the file.
   'If any lines are corrupt, report an error and continue parsing.
   While Not MyReader.EndOfData
   Try
   currentRow = MyReader.ReadFields()
   'ouput the second value of each line to show that the file has been parsed.
   MsgBox(currentRow(1))
   ' Include code here to handle the row.
   Catch ex As Microsoft.VisualBasic.FileIO.MalformedLineException
   MsgBox("Line " & ex.Message & _
   " is invalid. Skipping")
   End Try

   End While

   End Using

6. Execute the code in debug mode using the "F5" key.

7. Click on "Button1" to executed the parsing code. A message box for each line in the file will appear on the screen with the second value of that line displayed.

Tips & Warnings

• Altering the delimiter value in the code will allow this code to be used for multiple file types.

References

• Microsoft Field Parser Help