ASP.NET ListBox всегда возвращает первое значение (-1 выбранный индекс)

Question

У меня есть два ASP.NET ListBoxex в пользовательском контроле.Событие привязки данных запускается один раз.Я уверен, и я действительно проследил.но listbox всегда возвращает первое значение!это странно для меня.и я не знаю, как это исправить.Спасибо за помощь.Вот источник контроля пользователя:

<asp:UpdatePanel ID="updPanel" runat="server" ChildrenAsTriggers="true">
<ContentTemplate>
    <table class="style1">
        <tr>
            <td align="left" dir="rtl" valign="top" width="250">
                <asp:ListBox ID="lst2" runat="server" DataTextField="Title" 
                    DataValueField="Value" Font-Names="Tahoma" Font-Size="Small" Height="306px" 
                    Width="230px"></asp:ListBox>
            </td>
            <td align="right" dir="rtl" width="30">
                <table>
                    <tr>
                        <td width="25">
                            <asp:Button ID="btnAdd" runat="server" meta:resourcekey="btnAddResource1" 
                                Text="&gt;" Width="28px" />
                        </td>
                    </tr>
                    <tr>
                        <td>
                            <asp:Button ID="btnAddAll" runat="server" meta:resourcekey="btnAddAllResource1" 
                                Text="&gt;&gt;" Width="28px" />
                        </td>
                    </tr>
                    <tr>
                        <td>
                            <asp:Button ID="btnRemove" runat="server" meta:resourcekey="btnRemoveResource1" 
                                Text="&lt;" Width="28px" />
                        </td>
                    </tr>
                    <tr>
                        <td>
                            <asp:Button ID="btnRemoveAll" runat="server" 
                                meta:resourcekey="btnRemoveAllResource1" Text="&lt;&lt;" Width="28px" />
                        </td>
                    </tr>
                </table>
            </td>
            <td align="left" valign="top" width="250">
                <asp:ListBox ID="lst1" runat="server" DataTextField="Title" 
                    DataValueField="value" Font-Names="Tahoma" Font-Size="Small" Height="306px" 
                    Width="230px"></asp:ListBox>
            </td>
        </tr>
    </table>
</ContentTemplate>

, и вот мой код.

   Public Property UserName As String
    Get
        Return ViewState("UserName")
    End Get
    Set(ByVal value As String)
        ViewState("UserName") = value

    End Set
End Property
Protected Sub btnAdd_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnAdd.Click
    MsgBox(lst2.SelectedItem.Text)
End Sub

Public Sub BindUserNotInGroups()
    Dim objSecurity As New Negso.Security.SecurityHelper()
    Dim dt As New DataTable
    dt = objSecurity.GetNonGroupsForUser(UserName)
    lst2.DataValueField = dt.Columns("SID").ColumnName
    lst2.DataTextField = dt.Columns("Name").ColumnName
    lst2.DataSource = dt
    lst2.DataBind()
End Sub
''' <summary>
''' Binds the user not in groups.
''' </summary>
''' <remarks></remarks>
Public Sub BindUserInGroups()

    Dim objSecurity As New Negso.Security.SecurityHelper()
    'Dim k = objSecurity.GetGroupsForUser(UserName).Rows.Count
    Dim dt As New DataTable
    dt = objSecurity.GetGroupsForUser(UserName)
    lst1.DataValueField = dt.Columns("SID").ColumnName
    lst1.DataTextField = dt.Columns("Name").ColumnName
    lst1.DataSource = dt
    lst1.DataBind()
End Sub

Я вызываю функции привязки, когда свойство Username будет установлено:*

Public Property UserName() As String
    Get
        Return ViewState("UserName")
    End Get
    Set(ByVal value As String)

        ViewState("UserName") = value
        userGroups1.UserName = ViewState("UserName")
        userGroups1.BindUserInGroups()
        userGroups1.BindUserNotInGroups()
        'ListBox3.UserName = ViewState("UserName")
    End Set

Answer 1

В принципе это не лучший способ.Вы должны работать так:

public overrides sub onload()

if (not String.isNullOrEmpty(UserName) and not Page.IsPostBack) OR Me.UserNameChanged then

        userGroups1.UserName = Me.UserName
        userGroups1.BindUserInGroups()
        userGroups1.BindUserNotInGroups()


end if

end sub

ок, как-то так

Public Class testpage
    Inherits System.Web.UI.Page

    Private lst2 As New ListBox
    Private WithEvents btnadd As New Button


    Private _UserNameChanged As Boolean
    Public Property UserNameChanged() As Boolean
        Get
            Return _UserNameChanged
        End Get
        Set(ByVal value As Boolean)
            _UserNameChanged = value
        End Set
    End Property

    Public Property UserName As String
        Get
            Return ViewState("UserName")
        End Get
        Set(ByVal value As String)
            If ViewState("UserName") <> value Then
                UserNameChanged = True
            End If
            ViewState("UserName") = value
        End Set
    End Property

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        If Not Me.Page.IsPostBack And Not String.IsNullOrEmpty(UserName) Then
            Me.DataBind(True)
        End If

    End Sub

    Private Sub onbtnClick() Handles btnadd.Click

        If Me.UserNameChanged And Not String.IsNullOrEmpty(UserName) Then
            Me.DataBind(True)
        End If

    End Sub

    Public Overrides Sub DataBind()

        userGroups1.UserName = Me.UserName
        userGroups1.BindUserInGroups()
        userGroups1.BindUserNotInGroups()

        MyBase.DataBind()
    End Sub

End Class