不能将项目添加到SetDepter属性中的DropDownList

Question

我想添加一个项目到一个Setter中的DropDownList，并且添加的项目不保留。

我已经证实，ViewState是正确启用在这个问题（Switched to ASP.NET 3.5, DropDownList doesn't remember dynamically added items）

这里是我的代码提示。

Private Sub Page_Init(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Init 
     If ddlCountry.Items.Count < Country.GetList.Length Then 
      ddlCountry.DataSource = Country.GetList() 
      ddlCountry.DataBind() 
      'At this point, there are correctly 231 items in ddlCountry.' 
     End If 
    End Sub 

    Public WriteOnly Property Country() As String 
     Set(ByVal Value As String) 
      If ddlCountry.Items.FindByValue(Value.Country) Is Nothing Then 
       Dim li As New ListItem(Value.Country, Value.Country) 
       ddlCountry.Items.Insert(0, li) 
       ddlCountry.SelectedIndex = ddlCountry.Items.IndexOf(li) 
       'At this point, there are correctly 232 items in ddlCountry' 
      Else 
       ddlCountry.SelectedValue = Value.Country 
      End If 
     End Set 
    End Property 

    Private Sub Page_PreRender(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.PreRender 
     If ddlCountry.Items.FindByText("<-- Please Select-->") Is Nothing Then 
      'At this point, we are incorrectly' 
      'back to 231 items - this is the problem.' 
      ddlCountry.Items.Insert(0, New ListItem("<-- Please Select-->", "")) 
     End If 
    End Sub 

Answer 1

是否试图在下拉列表中将AppendDataBoundItems属性设置为true？