在 FromView 控件中使用 DropDownList

Question

我正在尝试让下拉列表控件在 FormView 中工作。我需要让列表成为某个表的过滤视图，并且仍然绑定到我正在编辑的数据中的字段。我尝试以编程方式设置项目数据，蚂蚁可以工作，但是数据绑定 不起作用，它尝试将 null 插入数据库。

这是我尝试过的代码。我也尝试在其他几个事件中做同样的事情，它仍然尝试将 null 插入数据库。

            <asp:DropDownList ID="lstManagers" runat="server" 
                OnDataBound ="ManagersLoad"
                SelectedValue='<%# Bind("UserName") %>' Width="100%" 
                DataSourceID="TimeOff" DataTextField="UserName" DataValueField="UserName">
            </asp:DropDownList>


Protected Sub ManagersLoad(ByVal sender As Object, ByVal e As System.EventArgs)
    Dim lst As DropDownList = FormView1.FindControl("lstManagers")
    'get list of managers
    Using ef As New TimeOffData.TimeOffEntities
        For Each item As ListItem In lst.Items
            Dim li As ListItem = item
            item.Text = (From x In ef.TimeOffUsers Where x.UserName = li.Value Select x.FirstName & " " & x.LastName).FirstOrDefault
        Next
    End Using
End Sub

Answer 1

我获取了控件的所有数据绑定内容，并决定手动完成它会更容易。我已将代码更改为这样

Protected Sub FormView1_ItemInserting(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.FormViewInsertEventArgs) Handles FormView1.ItemInserting
    Dim lst As DropDownList = FormView1.FindControl("lstManagers")
    e.Values.Item("ManagerName") = lst.SelectedValue
End Sub

Protected Sub ManagersLoad(ByVal sender As Object, ByVal e As System.EventArgs)
    Dim lst As DropDownList = FormView1.FindControl("lstManagers")
    'get list of managers
    Using ef As New TimeOffData.TimeOffEntities
        Dim mng = From x In ef.TimeOffUsers Where x.IsManager = True

        For Each item In mng
            lst.Items.Add(New ListItem(item.FirstName & " " & item.LastName, item.UserName))
        Next
    End Using
End Sub