Question

我正在尝试使用列表视图的下拉列表来过滤结果。

我已经更改了数据源的选择查询，如下所示......

列表视图：

<asp:AccessDataSource ID="AccessDataSource1" runat="server" 
        DataFile="~/App_Data/ASPNetDB.mdb" 
        SelectCommand="SELECT * FROM [tblNames] WHERE Surnames=@Surnames">
        <SelectParameters>
            <asp:ControlParameter ControlID="DropDownList1" Name="Surnames" 
                PropertyName="SelectedValue" />
        </SelectParameters>
    </asp:AccessDataSource>

下拉列表：

<asp:DropDownList ID="DropDownList1" runat="server" 
        DataSourceID="AccessDataSource2" DataTextField="Genre" 
        DataValueField="NameID" AppendDataBoundItems="true">
            <asp:ListItem Value="" Selected ="True" >All Surnames</asp:ListItem>
</asp:DropDownList>

    <asp:AccessDataSource ID="AccessDataSource2" runat="server" 
        DataFile="~/App_Data/ASPNetDB.mdb" SelectCommand="SELECT * FROM [tblSurnames]">
    </asp:AccessDataSource>

使用了正确的控件名称（完全相同的上限），但加载页面返回无法在ControlParameter'Surnames'中找到控件'DropDownList1'。

关于我在这里做错了什么建议？

编辑：如果有帮助，这是堆栈跟踪

[InvalidOperationException: Could not find control 'DropDownList1' in ControlParameter 'Surname'.]
   System.Web.UI.WebControls.ControlParameter.Evaluate(HttpContext context, Control control) +2107838
   System.Web.UI.WebControls.Parameter.UpdateValue(HttpContext context, Control control) +50
   System.Web.UI.WebControls.ParameterCollection.UpdateValues(HttpContext context, Control control) +113
   System.Web.UI.WebControls.SqlDataSource.LoadCompleteEventHandler(Object sender, EventArgs e) +46
   System.EventHandler.Invoke(Object sender, EventArgs e) +0
   System.Web.UI.Page.OnLoadComplete(EventArgs e) +9010786
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2350

Answer 1

ControlID需要以包含DropDownList的ContentPlaceHolder的ID作为前缀：

<asp:ControlParameter 
   Name="Surnames" 
   ControlID="ContentPlaceholderID$DropDownList1" 
   PropertyName="SelectedValue" 
/>

另请参阅：https://stackoverflow.com/a/5719348/124386

Answer 2

此外，请确保您对兴趣的控制权为runat =“server”。哎呀。

无法在ControlParameter'y'中找到控件'x'

2 个答案: