Cannot create a csv file from a datatable and dataview - vb.net

Question

I have code that produces a csv file (with headers) that contain fields identifying pixel locations of points of interest in selected images. Unfortunately, there are occasional duplicates that cause issues later in my production process. My plan to solve this is to open the csv file in the midst of the application, read the data into a data table, sort the data table with a data view using 4 sort keys (I am using the default Column1, Column2 etc) as i cannot figure out ho to use the real column header names contained in the first row. I have attempted to write the resulting rows to a new file, and I get the correct number of rows in the output csv file, but the data in the row is missing and i get a text string ' System.Data.DataRowView, not the 12 fields i was expecting.
In the code, my most recent attempt is to create a writeOutPutLine containing the concatenated contents of the row, in my desired sort order.
I have attempted to use CSVHelper with no success, and also tried about 10 other code sets posted on the various web sites.
Here is my code
Sub New_Csv_Sort()
Dim linecount As Integer = 1
Dim dt As DataTable = New DataTable
Dim dgv As DataGridView = New DataGridView
Dim TextLine As String = ""
Dim SplitLine() As String
Dim objReader As New System.IO.StreamReader(TargetFileName, Encoding.ASCII)
Dim ColumnCount As Integer = 0
For ColumnCount = 1 To 13 Step 1
dt.Columns.Add()
Next
Dim firstline As Boolean = True
Do While objReader.Peek() <> -1
TextLine = objReader.ReadLine()
SplitLine = Split(TextLine, ",")
dt.Rows.Add(SplitLine)
If FirstTime = True Then
' Here I was trying to use the first line to set the column labels but no joy
' For ColumnCount = 1 To 12 Step 1
' dt.datacolumn.
' Next
End If
Loop
' This next is commentted out in the sort statement because I could not get the column names to be recognised
'.Sort = "Datum ASC, Picture ASC, Y_Loc ASC, X_Loc, ASC"
Dim dv As New DataView(dt) With {
.Sort = "Column5 ASC, Column1 ASC, Column12 ASC, Column11 ASC"
}
FileOpen(SortedTargetFileNumber, SortedTargetFileName, OpenMode.Output)
'I have looked that the data and it is read in correctly
But my output line is trash!
For Each Rowview As DataRowView In dv
'WriteOutPutLine = dv.row
For Each DataColumn In dt.Columns
WriteOutPutLine = WriteOutPutLine & Row[col].tostring() & ","
Next
WriteOutPutLine = Rowview.ToString
PrintLine(SortedTargetFileNumber, WriteOutPutLine)
linecount = linecount + 1
Next
FileClose(SortedTargetFileNumber)
MsgBox("Sorted Lines = " & linecount)
End Sub

Answer 1

Sub New_Csv_Sort()
Dim dt As DataTable = New DataTable
Dim TextLine As String = ""
Dim SplitLine() As String
Dim objReader As New System.IO.StreamReader(TargetFileName, Encoding.ASCII)
Dim ColumnCount As Integer = 0
'Create columns for the data -
For ColumnCount = 1 To 13 Step 1
dt.Columns.Add()
Next
'Load the datatable
Do While objReader.Peek() <> -1
TextLine = objReader.ReadLine()
SplitLine = Split(TextLine, ",")
dt.Rows.Add(SplitLine)
Loop
'This is the sort order based on the header titles, but is translated the the default column name
'.Sort = "Datum ASC, Picture ASC, Y_Loc ASC, X_Loc ASC"
Dim dv As New DataView(dt) With {
.Sort = "Column5 ASC, Column1 ASC, Column12 ASC, Column11 ASC"
}
'Open the output file
FileOpen(SortedTargetFileNumber, SortedTargetFileName, OpenMode.Output)
'Create a string of all the rows in the dataview separated by commas
Dim DataLine As String = ""
For Each r As DataRowView In dv
DataLine &= String.Join(",", r.Row.ItemArray) & Environment.NewLine
Next
' Write the data to a file
WriteOutPutLine = DataLine
PrintLine(SortedTargetFileNumber, WriteOutPutLine)
FileClose(SortedTargetFileNumber)
' and we are done
End Sub

Answer 2

try this function
Private Function ConvertToCSV(ByVal dt As DataTable) As String
Dim sb As New Text.StringBuilder()
For Each row As DataRow In dt.Rows
sb.AppendLine(String.Join(",", (From i As Object In row.ItemArray Select i.ToString().Replace("""", """""").Replace(",", "\,").Replace(Environment.NewLine, "\" & Environment.NewLine).Replace("\", "\\")).ToArray()))
Next
Return sb.ToString()
End Function