How to place textboxes and other control on Datagridview - C#.Net

placeboxes.cs

 try
            {

                int r_left = 0, r_top = 0;
                DataGridViewCell cell;                

                cell = row.Cells[colLno.Index];

                r_left = dataGridView1.GetCellDisplayRectangle(cell.ColumnIndex, cell.RowIndex, false).Left;
                r_top = dataGridView1.GetCellDisplayRectangle(cell.ColumnIndex, cell.RowIndex, false).Top;
                ctxt_lno.Width = cell.Size.Width;
                ctxt_lno.Height = cell.Size.Height;
                ctxt_lno.Top = r_top + dataGridView1.Top;
                ctxt_lno.Left = r_left + dataGridView1.Left;
                ctxt_lno.Text = cell.Value != null ? cell.Value.ToString() : (row.Index + 1).ToString();
                }
                
         catch (Exception)
            {

                throw;
            }