'dgv= gebunden/Quelle, dgv2 ungebunden/Ziel
  With dgv
       dgv2.ColumnCount = .ColumnCount
       Dim rowcontent(.ColumnCount - 1) As String
 
       For Each datagridrow As DataGridViewRow In .SelectedRows
           For c As Integer = 0 To datagridrow.Cells.Count - 1
               rowcontent(c) = datagridrow.Cells(c).Value.ToString
           Next c
           dgv2.Rows.Add(rowcontent)
       Next datagridrow
  End With

   Dim s As String
   With dgv2
       .ClipboardCopyMode = _
         DataGridViewClipboardCopyMode.EnableWithoutHeaderText
       Clipboard.SetDataObject(.GetClipboardContent)
       s = Clipboard.GetText
       'Die Zeichenfolge in 's' kann durch io.writeallines gespeichert werden
   End With