C# การ Default ของ DataGridViewComboBoxColumnใน DataGridView

for (int i = 0; i < dvg.Rows.Count; i++)
{
	dvg.Rows[i].Cells["ComboColumnName"].Value = "string";
}

//combobox name = combobox_receive_material
            for (int i = 0; i < dataGridView1.Rows.Count; i++)
            {
                dataGridView1.Rows[i].Cells["combobox_receive_material"].Value = "ปกติ";
            }

string input_combobox = "SELECT * FROM statuses";
            SqlDataAdapter adapter = new SqlDataAdapter(input_combobox, conn);
            DataTable dt = new DataTable();
            adapter.Fill(dt);
            this.combobox_receive_material.DataSource = dt;     //this.combobox_receive_material คือ datagridviewconboboxcell
            this.combobox_receive_material.ValueMember = "id";           
            this.combobox_receive_material.DisplayMember = "name";

private void button2_Click_1(object sender, EventArgs e)
        {
            textboxEnable();
            foreach (DataGridViewRow item in dataGridView2.Rows)
            {
                if ((bool)item.Cells[0].Value == true)
                {
                    int n = dataGridView1.Rows.Add();
                    dataGridView1.Rows[n].Cells[0].Value = false;
                    dataGridView1.Rows[n].Cells[1].Value = item.Cells[1].Value.ToString();
                    dataGridView1.Rows[n].Cells[2].Value = item.Cells[2].Value.ToString();
                    dataGridView1.Rows[n].Cells[3].Value = item.Cells[3].Value.ToString();
                    dataGridView1.Rows[n].Cells[4].Value = item.Cells[4].Value.ToString();
                    dataGridView1.Rows[n].Cells[5].Value = item.Cells[5].Value.ToString();
                    dataGridView1.Rows[n].Cells[6].Value = item.Cells[6].Value.ToString();
                    dataGridView1.Rows[n].Cells[7].Value = item.Cells[7].Value.ToString();
                    dataGridView1.Rows[n].Cells[8].Value = item.Cells[8].Value.ToString();
                    dataGridView1.Rows[n].Cells[11].Value = item.Cells[9].Value.ToString();

                    
                }
            }

            //combobox name = combobox_receive_material
            for (int i = 0; i < dataGridView1.Rows.Count; i++)
            {
                dataGridView1.Rows[i].Cells["combobox_receive_material"].Value = "ปกติ";
            }

            List<DataGridViewRow> toDelete = new List<DataGridViewRow>();

            foreach (DataGridViewRow row in dataGridView2.Rows)
            {
                bool s = Convert.ToBoolean(row.Cells[0].Value);

                if (s == true)
                {
                    toDelete.Add(row);
                }
            }

            foreach (DataGridViewRow row in toDelete)
            {
                dataGridView2.Rows.Remove(row);
            }

            panelControl1.Visible = false;

           

        }

string input_combobox = "SELECT * FROM statuses";
            SqlDataAdapter adapter = new SqlDataAdapter(input_combobox, conn);
            DataTable dt = new DataTable();
            adapter.Fill(dt);
            this.combobox_receive_material.DataSource = dt;     //this.combobox_receive_material คือ datagridviewconboboxcell
            this.combobox_receive_material.ValueMember = "id";           
            this.combobox_receive_material.DisplayMember = "name";
            this.combobox_receive_material.DataPropertyName = ? // ตัวนี้หายไป

            for (int i = 0; i < dataGridView1.Rows.Count; i++)
            {
                dataGridView1.Rows[i].Cells["combobox_receive_material"].Value = 1; // "id" 
            }

private void button2_Click_1(object sender, EventArgs e)
        {
            textboxEnable();
            foreach (DataGridViewRow item in dataGridView2.Rows)
            {
                if ((bool)item.Cells[0].Value == true)
                {
                    int n = dataGridView1.Rows.Add();
                    dataGridView1.Rows[n].Cells[0].Value = false;
                    dataGridView1.Rows[n].Cells[1].Value = item.Cells[1].Value.ToString();
                    dataGridView1.Rows[n].Cells[2].Value = item.Cells[2].Value.ToString();
                    dataGridView1.Rows[n].Cells[3].Value = item.Cells[3].Value.ToString();
                    dataGridView1.Rows[n].Cells[4].Value = item.Cells[4].Value.ToString();
                    dataGridView1.Rows[n].Cells[5].Value = item.Cells[5].Value.ToString();
                    dataGridView1.Rows[n].Cells[6].Value = item.Cells[6].Value.ToString();
                    dataGridView1.Rows[n].Cells[7].Value = item.Cells[7].Value.ToString();
                    dataGridView1.Rows[n].Cells[8].Value = item.Cells[8].Value.ToString();
                    dataGridView1.Rows[n].Cells[11].Value = item.Cells[9].Value.ToString();
                    dataGridView1.Rows[n].Cells["combobox_receive_material"].Value = "ปกติ";
                    dataGridView2.Rows.Remove(item );
                }
            }

            panelControl1.Visible = false;
        }