Writing CSV with quotes to match source file - using VB.net, and TextfieldParser

Sorry, very casual programmer, haven't coded in many years ..(primarily in VB6) I have googled, and read .net details on each file class, seen lots of examples, but have no idea how to get modified output to match source formatting.

I have existing file: (This is 2 lines of file: Header, and 1 detail)

"BATCHNBR","JOURNALID","TRANSNBR","DESCOMP","ROUTE","ACCTID","COMPANYID","TRANSAMT","TRANSQTY","SCURNDEC","SCURNAMT","HCURNCODE","RATETYPE","SCURNCODE","RATEDATE","CONVRATE","RATESPREAD","DATEMTCHCD","RATEOPER","TRANSDESC","TRANSREF","TRANSDATE","SRCELDGR","SRCETYPE","COMMENT","VALUES","PROCESSCMD"
"000004","00001","0000000020","",0,"60000000000000000ZZZZZ","GMN",817.31,0,"2",817.31,"USD","SP","USD",20180511,1,0,"1","1","100123","10444-Kampwerth, Brooke E",20180511,"UP","SC","",0,0

I have the sub complete but it outputs each field on it's own line, and without double quotes. TextFieldParser does not have write methods. The msgbox embeds indicate I have replaced the data correctly,

I am Truncating a certain field(if Required), and The msgbox embeds indicate I have replaced the data correctly.

I just need to output in the same strings as source.

Private Sub cmdProcess_Click(sender As Object, e As EventArgs) Handles cmdProcess.Click


    Using sw = New IO.StreamWriter(NewFile)
        Using MyReader As New FileIO.TextFieldParser(oFile)

            MyReader.TextFieldType = FileIO.FieldType.Delimited
            MyReader.SetDelimiters(",")
            'MyReader.HasFieldsEnclosedInQuotes

            'Dim Expression As String
            Dim Replacement As String

            Dim currentRow As String()
            While Not MyReader.EndOfData
                Try
                    currentRow = MyReader.ReadFields()
                    Dim currentField As String
                    For Each currentField In currentRow
                        If Strings.Right(currentField, 3) = "ZZZ" Then
                            'MsgBox(MyReader.LineNumber & " " & currentField)
                            Replacement = Strings.Left(currentField, 6)
                            'MsgBox(MyReader.LineNumber & " " & Replacement)
                            currentField = Replacement
                        End If
                        sw.WriteLine(String.Join(",", currentField))
                    Next
                Catch ex As Microsoft.VisualBasic.
                            FileIO.MalformedLineException
                    MsgBox("Line " & ex.Message &
                    "is not valid and will be skipped.")
                End Try
            End While
        End Using
    End Using
    MsgBox("Done")
    Dispose()

    Application.Exit()
End Sub

If I replace the currentfield with currentrow in sw.writeline, it the outputs the same line 27 time (27 rows in source), then does the next line. And without double quotes around each field.

Current Output: (Single Spaced)

BATCHNBR

JOURNALID

TRANSNBR

DESCOMP

ROUTE

What am I missing .. ??

Solution

You need to move the WriteLine outside of For...Next loop so it only writes one line per row. I used a list to accumulate the strings in each row. The the list is used in the Join.

Dim lstRow as New List(Of String)
 For Each currentField In currentRow

        If Strings.Right(currentField, 3) = "ZZZ" Then
            'MsgBox(MyReader.LineNumber & " " & currentField)
            Replacement = Strings.Left(currentField, 6)
            'MsgBox(MyReader.LineNumber & " " & Replacement)
            currentField = Replacement
        End If
        lstRow.Add(currentField)
    Next
    sw.WriteLine(String.Join(",", lstRow))
    lstRow.Clear()