搞了好几天都不行，急死了，数据邦定控件中的模板到底怎么回事？

Question

FormView
我在其EditTemplate中放了2个DropDownList也就是希望在编辑状态下操作时，对于下拉框1中的值改变时，Postback刷新一下下拉框2中的可选项值，也就是联动但总是提示如下错误：=========================================================
用户代码未处理 System.InvalidOperationException
  Message="Eval()、XPath() 和 Bind() 这类数据绑定方法只能在数据绑定控件的上下文中使用。"
  Source="System.Web"
  StackTrace:
       在 System.Web.UI.Page.GetDataItem()
       在 System.Web.UI.TemplateControl.Eval(String expression)
       在 ASP.order_ordermain_aspx.__DataBinding__control53(Object sender, EventArgs e) 位置 d:\Documents and Settings\Administrator\My Documents\Visual Studio 2005\Projects\OCRS_NET\Order\OrderMain.aspx:行号 167
       在 System.Web.UI.Control.OnDataBinding(EventArgs e)
       在 System.Web.UI.WebControls.ListControl.OnDataBinding(EventArgs e)
       在 System.Web.UI.WebControls.ListControl.PerformSelect()
       在 System.Web.UI.WebControls.BaseDataBoundControl.DataBind()
       在 System.Web.UI.WebControls.BaseDataBoundControl.EnsureDataBound()
       在 System.Web.UI.WebControls.BaseDataBoundControl.OnPreRender(EventArgs e)
       在 System.Web.UI.WebControls.ListControl.OnPreRender(EventArgs e)
       在 System.Web.UI.Control.PreRenderRecursiveInternal()
       在 System.Web.UI.Control.PreRenderRecursiveInternal()
       在 System.Web.UI.Control.PreRenderRecursiveInternal()
       在 System.Web.UI.Control.PreRenderRecursiveInternal()
       在 System.Web.UI.Control.PreRenderRecursiveInternal()
       在 System.Web.UI.Control.PreRenderRecursiveInternal()
       在 System.Web.UI.Control.PreRenderRecursiveInternal()
       在 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

Answer 1

<EditItemTemplate>
      <p align="justify">
          <table>
              <tr>
                  <td align="right" style="height: 26px">
                      <asp:Label ID="Label9" runat="server" Text="订单编号："></asp:Label></td>
                  <td align="left" style="height: 26px">
                      <asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("sOrder_no") %>' Width="185px" ReadOnly="True"></asp:TextBox></td>
                  <td align="right" style="height: 26px">
                      <asp:Label ID="Label10" runat="server" Text="购买总数量："></asp:Label></td>
                  <td align="left" style="height: 26px; width: 158px;">
                      <asp:TextBox ID="TextBox2" runat="server" Text='<%# Bind("fTotalCount") %>' Width="100px" ReadOnly="True"></asp:TextBox></td>
              </tr>
              <tr>
                  <td align="right" style="height: 26px">
                      <asp:Label ID="Label2" runat="server" Text="销售单位："></asp:Label></td>
                  <td align="left" style="height: 26px">
                      <asp:TextBox ID="TextBox6" runat="server" Text='<%# Bind("sCompany_no") %>' Width="185px" ReadOnly="True"></asp:TextBox></td>
                  <td align="right" style="height: 26px">
                      <asp:Label ID="Label5" runat="server" Text="单据方式：" Width="97px"></asp:Label></td>
                  <td align="left" style="height: 26px; width: 158px;">
                      <asp:DropDownList ID="ddlBillCL" runat="server" Width="104px" DataSourceID="ObjectDataSource_BillClass" DataTextField="sBillCLName" DataValueField="sBillCLNo">
                      </asp:DropDownList></td>
              </tr>
              <tr>
                  <td align="right" style="height: 26px">
                      <asp:Label ID="Label1" runat="server" Text="客商名称：" Width="97px"></asp:Label></td>
                  <td align="left" style="height: 26px">
                      <asp:TextBox ID="TextBox7" runat="server" Text='<%# Bind("sCustb_name") %>' Width="186px" ReadOnly="True"></asp:TextBox></td>
                  <td align="right" style="height: 26px">
                      <asp:Label ID="Label13" runat="server" Text="结算类型：" Width="97px"></asp:Label></td>
                  <td align="left" style="height: 26px; width: 158px;">
                      <asp:DropDownList ID="ddlJSType" runat="server" Width="104px">
                          <asp:ListItem Value="1">按吨数</asp:ListItem>
                          <asp:ListItem Value="0">按金额</asp:ListItem>
                      </asp:DropDownList></td>  
              </tr>
              <tr>
                  <td align="right" style="height: 24px">
                      <asp:Label ID="Label3" runat="server" Text="场地名称："></asp:Label></td>
                  <td align="left" style="height: 24px">
                      <asp:DropDownList ID="ddlMeiChang" runat="server" Width="190px" DataSourceID="ObjectDataSource_MeiChang" DataTextField="sMC_name" DataValueField="sMeiChang_no" AutoPostBack="True" SelectedValue='<%# Bind("sMeiChang_no") %>'>
                      </asp:DropDownList></td>
                  <td align="right" style="height: 24px">
                      <asp:Label ID="Label4" runat="server" Text="磅房名称：" Width="97px"></asp:Label></td>
                  <td align="left" style="height: 24px; width: 158px;">
                      <asp:DropDownList ID="ddlBangfang" runat="server" Width="105px" DataSourceID="ObjectDataSource_BangFang" DataTextField="sBF_name" DataValueField="sBangFang_no">
                      </asp:DropDownList>
                      <asp:TextBox ID="tbBangFang" runat="server" Text='<%# Bind("sBangFang_no") %>' Visible="False"></asp:TextBox></td>
              </tr>
              <tr>
                  <td align="right" style="height: 24px">
                      <asp:Label ID="Label6" runat="server" Text="工作流：" Width="78px"></asp:Label></td>
                  <td align="left" style="height: 24px">
                      <asp:DropDownList ID="ddlWorkFlow1" runat="server" Width="188px" DataSourceID="ObjectDataSource_WorkFlow" DataTextField="sWorkFlow_name" DataValueField="sWorkFlow_no" SelectedValue='<%# Bind("sWorkFlow_name") %>'>
                      </asp:DropDownList></td>
                  <td align="right" style="height: 24px">
                      <asp:Label ID="Label7" runat="server" Text="转零售工作流：" Width="160px"></asp:Label></td>
                  <td align="left" style="height: 24px; width: 158px;">
                      <asp:DropDownList ID="ddlWorkFlow2" runat="server" Width="104px" DataSourceID="ObjectDataSource_WorkFlow" DataTextField="sWorkFlow_name" DataValueField="sWorkFlow_no" SelectedValue='<%# Bind("sWorkFlow_name2") %>'>
                      </asp:DropDownList></td>
              </tr>
              <tr>
                  <td align="right" style="height: 26px">
                      <asp:Label ID="Label11" runat="server" Text="建单时间：" Width="97px"></asp:Label></td>
                  <td align="left" style="height: 26px">
                      <asp:TextBox ID="TextBox3" runat="server" Text='<%# Bind("dCreateTime") %>' Width="180px" ReadOnly="True"></asp:TextBox></td>
                  <td align="right" style="height: 26px">
                      <asp:Label ID="Label8" runat="server" Text="状态：" Width="97px"></asp:Label></td>
                  <td align="left" style="height: 26px; width: 158px;">
                      <asp:TextBox ID="TextBox4" runat="server" Width="100px" ReadOnly="True" Text='<%# Bind("sBillStatus") %>'></asp:TextBox></td>
              </tr>
          </table>
      </p>
      <asp:LinkButton ID="UpdateButton" runat="server" CausesValidation="True" CommandName="Update"
          Text="更新"></asp:LinkButton>
      <asp:LinkButton ID="UpdateCancelButton" runat="server" CausesValidation="False" CommandName="Cancel"
          Text="取消"></asp:LinkButton>
  </EditItemTemplate>

Answer 2

就是其中的这两行
===========================================================
<tr>
                  <td align="right" style="height: 24px">
                      <asp:Label ID="Label3" runat="server" Text="场地名称："></asp:Label></td>
                  <td align="left" style="height: 24px">
                      <asp:DropDownList ID="ddlMeiChang" runat="server" Width="190px" DataSourceID="ObjectDataSource_MeiChang" DataTextField="sMC_name" DataValueField="sMeiChang_no" AutoPostBack="True" SelectedValue='<%# Bind("sMeiChang_no") %>'>
                      </asp:DropDownList></td>
                  <td align="right" style="height: 24px">
                      <asp:Label ID="Label4" runat="server" Text="磅房名称：" Width="97px"></asp:Label></td>
                  <td align="left" style="height: 24px; width: 158px;">
                      <asp:DropDownList ID="ddlBangfang" runat="server" Width="105px" DataSourceID="ObjectDataSource_BangFang" DataTextField="sBF_name" DataValueField="sBangFang_no">
                      </asp:DropDownList>
                      <asp:TextBox ID="tbBangFang" runat="server" Text='<%# Bind("sBangFang_no") %>' Visible="False"></asp:TextBox></td>
              </tr>

Answer 3

写错了，应该是这样：<tr>
                  <td align="right" style="height: 24px">
                      <asp:Label ID="Label3" runat="server" Text="场地名称："></asp:Label></td>
                  <td align="left" style="height: 24px">
                      <asp:DropDownList ID="ddlMeiChang" runat="server" Width="190px" DataSourceID="ObjectDataSource_MeiChang" DataTextField="sMC_name" DataValueField="sMeiChang_no" AutoPostBack="True" SelectedValue='<%# Bind("sMeiChang_no") %>'>
                      </asp:DropDownList></td>
                  <td align="right" style="height: 24px">
                      <asp:Label ID="Label4" runat="server" Text="磅房名称：" Width="97px"></asp:Label></td>
                  <td align="left" style="height: 24px; width: 158px;">
                      <asp:DropDownList ID="ddlBangfang" runat="server" Width="105px" DataSourceID="ObjectDataSource_BangFang" DataTextField="sBF_name" DataValueField="sBangFang_no" SelectedValue='<%# Bind("sBangFang_no") %>'>
                      </asp:DropDownList>
                  </td>
              </tr>

Answer 4

原来是。net2005呀，不好意思不熟。 
不过我还是看得不太明白，你的控制联动的代码呢？难道vs2005里面不需要写后台代码？
第一个dropdownlist 的
SelectedValue='<%# Bind("sMeiChang_no") %>' 一旦更改，就能自动触发DataSourceID="ObjectDataSource_BangFang" 也发生更改吗？