Reading a .CSV File in VB .Net (2008)

The CSV file specs I followed can be read into / written from MS-Excel

Note: This code was taken from VB 6, so it may not be the best .Net code

   Public Function ParseLineExcel(ByRef strLine As String) As String
      'the string will be altered
      'From my VB 6 Library
      'Excel's formula SEEMS t be when quotes and commas are all mixed in
      'ODD number of quotes before a comma - the comma is part of the DATA
      'EVEN ------------------------------------------------------------------------------ DELIMETER
      'ODD => open => DATA
      'EVEN = closed =. valid delimeter

      Const ASCIIQUOTE As Long = 34                                                     '(")
      Const ASCIICOMMA As Long = 44 '(,)

      Dim strBuild As String = ""                                                                     'Start with an empty string
      Dim bOpen As Boolean = False                                                               '0 is an EVEN number for us right now
      Dim chChar As Char

      'Get nothing, give nothing
      If strLine.Length = 0 Then
         ParseLineExcel = ""
         Exit Function
      End If

      'String is just the last delimeter - return nothing!
      If (strLine.Length = 1) And (Asc(strLine) = ASCIIQUOTE Or Asc(strLine) = ASCIICOMMA) Then
         strLine = ""                                                                                      'Make sure that the line now contains NOTHING
         ParseLineExcel = ""                                                                        'And gove nothing for just a delimeter
         Exit Function
      End If

      'If we're pass the bogus calls, lets start working!
      chChar = strLine.Substring(0, 1)
      Do While strLine.Length > 0

         If Asc(chChar) = ASCIIQUOTE Then
            If strLine.Length = 1 Then                                                               'Assume last quote
               ParseLineExcel = strBuild                                                            'Last AQuote just dropped
               strLine = ""                                                                                   'Empty outthe incoming string
               Exit Function
            End If
            bOpen = Not bOpen                                                                         'Toggle the flag
         End If

         If (Asc(chChar) = ASCIICOMMA) And (Not bOpen) Then            'Data closed, it's a delimeter
            strLine = strLine.Substring(1)                                                         'Dump delimiting comma
            If strBuild.Length > 0 Then
               If Asc(Right(strBuild, 1)) = ASCIIQUOTE Then
                  strBuild = strBuild.Substring(0, strBuild.Length - 1)               'Return WITHOUT closing quote
               End If
            End If
            ParseLineExcel = strBuild
            Exit Function
         End If

         'Drop the opening "
         If Not ((Asc(chChar) = ASCIIQUOTE) And (strBuild.Length = 0)) Then
            strBuild = strBuild + chChar
         End If

         strLine = strLine.Substring(1)                                                              'Drop first char, string becomes "the rest"
         chChar = strLine.Substring(0, 1)                                                          'Get the first char
      Loop

      If strBuild.Trim.Length = 0 Then
         ParseLineExcel = ""
      Else
         ParseLineExcel = strBuild
      End If

   End Function

Revised   Jan 13, 2010