DataGridView to CSV File - vb.net

Question

I have a VB 2010 Express Project, that has a DataGridView in it, that I am trying to write to a CSV file.
I have the write all working. But its slow. Slow = maybe 30 seconds for 6000 rows over 8 columns.
Here is my code:
Private Sub btnExportData_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnExportData.Click
Dim StrExport As String = ""
For Each C As DataGridViewColumn In DataGridView1.Columns
StrExport &= """" & C.HeaderText & ""","
Next
StrExport = StrExport.Substring(0, StrExport.Length - 1)
StrExport &= Environment.NewLine
For Each R As DataGridViewRow In DataGridView1.Rows
For Each C As DataGridViewCell In R.Cells
If Not C.Value Is Nothing Then
StrExport &= """" & C.Value.ToString & ""","
Else
StrExport &= """" & "" & ""","
End If
Next
StrExport = StrExport.Substring(0, StrExport.Length - 1)
StrExport &= Environment.NewLine
Next
Dim tw As IO.TextWriter = New IO.StreamWriter("C:\Test1.CSV")
tw.Write(StrExport)
tw.Close()
End Sub
Does anyone know what I can do to speed it up?
thanks

Answer 1

Don't you just love it when you spend hours searching, then post a question, and a few minutes later find the answer yourself?
This did the trick for me:
Dim headers = (From header As DataGridViewColumn In DataGridView1.Columns.Cast(Of DataGridViewColumn)() _
Select header.HeaderText).ToArray
Dim rows = From row As DataGridViewRow In DataGridView1.Rows.Cast(Of DataGridViewRow)() _
Where Not row.IsNewRow _
Select Array.ConvertAll(row.Cells.Cast(Of DataGridViewCell).ToArray, Function(c) If(c.Value IsNot Nothing, c.Value.ToString, ""))
Using sw As New IO.StreamWriter("csv.txt")
sw.WriteLine(String.Join(",", headers))
For Each r In rows
sw.WriteLine(String.Join(",", r))
Next
End Using
Process.Start("csv.txt")