給Winform中的datagridview新增行號

private void dataGridView1_RowPostPaint(object sender, DataGridViewRowPostPaintEventArgs e)
        {
            SolidBrush brushOne = new SolidBrush(Color.Red);
            e.Graphics.DrawString(Convert.ToString(e.RowIndex + 1, System.Globalization.CultureInfo.CurrentUICulture), e.InheritedRowStyle.Font, brushOne, e.RowBounds.Location.X + 20, e.RowBounds.Location.Y + 4);
        }