如何在FormView控件的EditItemTemplate中绑定dropdownlist？

Question

将 Visual Web Developer Express 2010 与 ASP.NET 4.0 结合使用。

我有一个 FormView，我想从数据库设置默认值。我无法将其绑定到数据库中的值。我的 FormView 看起来像这样：

<asp:FormView 
ID="frmOrderDetails" 
DataSourceID="sdsFormOrderDetails" 
runat="server" 
DataKeyNames="orderId">

<EditItemTemplate>
    <h3>Edit Order Details</h3>

    <asp:Label ID="lblStrategy" Text="Strategy:" AssociatedControlID="ddlStrategies" runat="server"  />
    <asp:DropDownList SelectedValue='<%# Bind("strategyId") %>'
    ID="ddlStrategies" 
    runat="server" 
    DataTextField="strategy" 
    DataValueField="strategyId" 
    DataSourceID="sdsStrategies"
     />

    <asp:LinkButton
    id="lnkUpdate"
    Text="Update Order"
    CommandName="Update"
    Runat="server" />
    |
    <asp:LinkButton
    id="lnkCancel"
    Text="Cancel"
    CommandName="Cancel"
    Runat="server" />

</EditItemTemplate>
</asp:FormView>

<asp:SqlDataSource ID="sdsFormOrderDetails" runat="server" 
    ConnectionString="<%$ ConnectionStrings:LocalSQLServer %>" 
    ProviderName="<%$ ConnectionStrings:LocalSQLServer.ProviderName %>"  
    SelectCommand="usp_GetOrderDetails" SelectCommandType="StoredProcedure" 
    UpdateCommand="usp_UpdateOrder" UpdateCommandType="StoredProcedure">
    <SelectParameters>
        <asp:ControlParameter Name="orderId" ControlID="grdOrders" PropertyName="SelectedDataKey.Value" />
    </SelectParameters>
    <UpdateParameters>
        <asp:ControlParameter Name="orderId" ControlID="grdOrders" />
    </UpdateParameters>
</asp:SqlDataSource>                     

<asp:SqlDataSource ID="sdsStrategies" runat="server"
    ConnectionString="<%$ ConnectionStrings:LocalSQLServer %>" 
    ProviderName="<%$ ConnectionStrings:LocalSQLServer.ProviderName %>"  
    SelectCommand="usp_GetStrategiesDropDown">   
</asp:SqlDataSource>    

当我单击 FormView 控件上的编辑按钮时，EditItemTemplate 甚至不会加载，但也没有收到错误消息。

Answer 1

您需要执行以下操作将 DropDownList 绑定到 EditItemTemplate：

1. 将 DropDownList 及其 DataSource 添加到编辑项目模板。

2. 设置DropDownList参数：

   DataSourceID="SqlDataSourceDropDownlist" SelectedValue=<%# Bind("ValueToBind") %>
   DataTextField="ValueToDisplay" DataValueField="ValueToBind"
   

3. 设置 ListView / FormView 数据源:

Answer 2

您需要使用 formview Databound 事件，例如

 protected void frmOrderDetails_DataBound(object sender, EventArgs e)
{
    if (frmOrderDetails.CurrentMode == FormViewMode.Edit)
    {
        DropDownList ddlStrategies = (DropDownList)frmOrderDetails.FindControl("ddlStrategies");
        ddlStrategies.SelectedValue = Your DB Value Goes here;
    }
}