dataGridView中DataGridViewComboBoxColumn问题

Question

dataGridView中有一个DataGridViewComboBoxColumn 列
1、是这样绑定的：   productName.DataSource = ds.Tables[0];
            productName.DisplayMember = "productName";
            productName.ValueMember = "id";
2、存到数据库是是存的dataGridView1["productName", j].value
3、从数据库中取值的时候赋值给dataGridView1["productName",i].Value= ds.Tables[0].Rows[i]["productId"].ToString();   
   时报错DataGridComboBoxCell value is not valid.

Answer 1

DataGridViewComboBoxColumn1.DataPropertyName = "绑定的字段";

Answer 2

ds.Tables[0].Rows[i]["productId"]
它的值是不是NULL呀

Answer 3

或者ds.Tables[0].Rows[i]["productId"]在 productName中与这个DisplayMember 没有对应的ValueMember 呀

Answer 4

  
private DataSet dataSource;
private System.Windows.Forms.BindingSource bdsPurchaseMain;
          dataSource = purchaseMainBLL.GetAllList();
            bdsPurchaseMain.DataSource = dataSource;
            bdsPurchaseMain.DataMember = "PurchaseMain";

Answer 5

            dgvPurchaseSub.DataSource = bdsPurchaseMain;
            dgvPurchaseSub.DataMember = "FK_PurchaseMain_PurchaseSub";
private MasterSoft.WinUI.MDataGridViewComboBoxColumn colCboGoodsNo;
this.colCboGoodsNo = new MasterSoft.WinUI.MDataGridViewComboBoxColumn();
            //
            // colCboGoodsNo
            //
            this.colCboGoodsNo.DataPropertyName = "GoodsNo";
            this.colCboGoodsNo.HeaderText = "物品编号";
            this.colCboGoodsNo.Name = "colCboGoodsNo";