How to add combobox to datagridview in c#

            DataGridViewComboBoxCell gridCombo = new DataGridViewComboBoxCell();
            da = new SqlDataAdapter("SELECT dept FROM department ", cn.Con());
            ds = new DataSet();
            da.Fill(ds);
            dt = ds.Tables[0];
            gridCombo.Items.Clear();
            for (int i = 0; i < dt.Rows.Count; i++)
            {

                gridCombo.Items.Add(dt.Rows[i].ItemArray[0]);
            }

            dataGridView2[1, dataGridView2.Rows.GetLastRow(DataGridViewElementStates.Visible)] = gridCombo;