Impossible d'ajouter l'élément à DropDownList dans la propriété Setter dans ASP .NET

Question

J'essaie d'ajouter un élément à une DropDownList dans un Setter, et l'élément ajouté ne reste pas.

Je confirme que Viewstate est correctement activé comme suggéré dans cette question (Switched to ASP.NET 3.5, DropDownList doesn't remember dynamically added items)

Voici mon code.

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

Vous avez essayé de définir la propriété AppendDataBoundItems sur true dans la liste déroulante?