datagridview上显示控件问题


if (this.dataGridView1.CurrentCell.ColumnIndex == 5)
                    {
                        Rectangle rect = dataGridView1.GetCellDisplayRectangle(dataGridView1.CurrentCell.ColumnIndex, dataGridView1.CurrentCell.RowIndex, false);                        btnDesignEmpID.Left = rect.Left;
                        btnDesignEmpID. = rect.Top;
                        btnDesignEmpID.Width = rect.Width;
                        btnDesignEmpID.Height = rect.Height;
                        if (dataGridView1.CurrentCell.Value != null)
                        {
                            //btnDesignEmpID.Text = dataGridView1.CurrentCell.Value.ToString();
                        }
                        btnDesignEmpID.Visible = true;
                        //dataGridView1.CurrentCell.Value = dtpDesignFinishyj.Text;
                    }
                    else
                    {
                        btnDesignEmpID.Visible = false;
                    }
单击单元格是会显示控件，我用cmb的时候显示正常的，换成btn时怎么显示在单元格上面了？？