ASP.NET GridView 内嵌 DropDownList 绑定数据

aspx页面代码：

.cs代码： 绑定下拉数据源

        public List GetDate()
        {
            List info = new List();
            using (this.context = new SDKDataContext())
            {
                var date = from c in this.context.DateInfo select c;
            }
            return info;
        }

给下拉显示初始数据

        public void BandingGridView()
        {
            using (this.context = new SDKDataContext())
            {
                var vData = from c in this.datacontext.DateInfo select c;
                this.GridView2.DataSource = vData;
                this.GridView2.DataBind();
                foreach (GridViewRow gvr in GridView2.Rows)
                {
                    DropDownList ddl = (DropDownList)gvr.FindControl("DropDownList2");
                    DateInfo info = new DateInfo();
                    info = vData[rows];
                    ddl.SelectedValue = info.Val.ToString();
                }
            }
        }