C#.Net - Displaying Sno in DataGridView

private void dGvCapacity_RowPostPaint(object sender, DataGridViewRowPostPaintEventArgs e)

        {

            try

            {

                string strRowNumber = (e.RowIndex + 1).ToString();

                SizeF size = e.Graphics.MeasureString(strRowNumber, this.Font);

                if (dGvCapacity.RowHeadersWidth < (int)(size.Width + 20))

                {

                    dGvCapacity.RowHeadersWidth = (int)(size.Width + 20);

                }

                Brush b = SystemBrushes.ControlText;

                e.Graphics.DrawString(strRowNumber, this.Font, b, e.RowBounds.Location.X + 15, e.RowBounds.Location.Y + ((e.RowBounds.Height - size.Height) / 2));

            }

            catch (Exception ex)

            {

            }

        }