Group rows in DataGridView

in the DataGridView place the following code in the

dgvProduct_CellFormatting Event

If e.RowIndex > 0 And e.ColumnIndex = 0 Then
                If dgvProduct.Item(0, e.RowIndex - 1).Value = e.Value Then
                    e.Value = ""
                ElseIf e.RowIndex < dgvProduct.Rows.Count - 1 Then
                    dgvProduct.Rows(e.RowIndex).DefaultCellStyle.BackColor = Color.White
                End If
End If

All done!

Enjoy

You could try using the functionality of MSFlexGrid's MergeCells property of vertical cell merging instead of row grouping as explained in this article DataGridView Grouping in C#/VB.NET: Two Recipes. In this example, rows which belong to a group are joined visually using cells merged vertically - instead of using classical horizontal group rows.

protected override void OnCellPainting(DataGridViewCellPaintingEventArgs args)
{
  base.OnCellPainting(args);

  args.AdvancedBorderStyle.Bottom =
    DataGridViewAdvancedCellBorderStyle.None;

  // Ignore column and row headers and first row
  if (args.RowIndex < 1 || args.ColumnIndex < 0)
    return;

  if (IsRepeatedCellValue(args.RowIndex, args.ColumnIndex))
  {
    args.AdvancedBorderStyle.Top =
      DataGridViewAdvancedCellBorderStyle.None;
  }
  else
  {
    args.AdvancedBorderStyle.Top = AdvancedCellBorderStyle.Top;
  }
}