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在加载页面之前，我使用子例程将 DropDownList 控件链接在一起：

Private Sub CreateCascadingDropDown(ByVal category As String, ByRef parentDDL As DropDownList, ByRef targetDDL As DropDownList)
            Dim CDDL As New CascadingDropDown
            With CDDL
                .Category = category
                If Not parentDDL Is Nothing Then
                    parentDDL.Items.Clear()
                    .ParentControlID = parentDDL.ID
                End If
                targetDDL.Items.Clear()
                .TargetControlID = targetDDL.ID
                .PromptText = SharedWeb.GC_SELECTONE
                .PromptValue = "-1"
                .LoadingText = "Please wait..."
                .ServicePath = "/ajax/InvestmentProcess.asmx"
                .ServiceMethod = "GetTaxo"
            End With
            'Page.ClientScript.RegisterForEventValidation(CDDL.UniqueID)
            targetDDL.Parent.Controls.Add(CDDL)
        End Sub

当调用 Web 服务方法时，它会执行以下代码。根据类别，它从适配器获取适当的数据。

<WebMethod()> _
    Public Function GetTaxo(ByVal knownCategoryValues As String, ByVal category As String) As CascadingDropDownNameValue()
        Dim log As ILog = LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType)
        log.Debug("GetSegmentTaxonomy(" + category + ") -> {" + knownCategoryValues + "}")
        Dim kv As StringDictionary = CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues)
        Dim adapter As New SegmentTaxonomyTableAdapters.SEGMENT_ARCHITECTURE_TableAdapter
        Dim rows As DataRowCollection

        Select Case category
            Case InvestmentEdit.ST_SEG_ARCH
                rows = New SegmentTaxonomyTableAdapters.SEGMENT_ARCHITECTURE_TableAdapter().GetData().Rows
            Case InvestmentEdit.ST_LOB
                If kv.ContainsKey(InvestmentEdit.ST_SEG_ARCH) Then
                    log.Debug("found seg architecture - > " + kv(InvestmentEdit.ST_SEG_ARCH))
                    rows = New SegmentTaxonomyTableAdapters.LINE_OF_BUSINESSTableAdapter().GetData(kv(InvestmentEdit.ST_SEG_ARCH)).Rows
                End If
        End Select

        If Not rows Is Nothing Then
            Dim results As New List(Of CascadingDropDownNameValue)
            For Each row As DataRow In rows
                log.Debug("ROW >>>> " + row("lov_label").ToString() + " : " + row("lov_cd").ToString())
                results.Add(New CascadingDropDownNameValue(row("lov_label"), row("lov_cd")))
            Next
            Return results.ToArray
        End If
        Return Nothing
    End Function

我需要将大约 5 个下拉菜单链接在一起。如果顶层下拉控件 (myDDL) 是唯一这样链接的控件，则它可以正常加载：

CreateCascadingDropDown("MyCat",Nothing,myDDL)

但是当我链接第二个下拉控件时，Internet Explorer 会给出脚本超时。如果我继续允许脚本运行，它只会一直给我提示。如果选择停止运行脚本，我会收到方法错误 12031 或错误 500（是的，我的 Web 服务文件中有 ScriptService() 声明）。关于造成这种情况的任何想法？

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1 回答 1

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事实证明，我只需要从 Ajax 控件工具包中添加以下控件：

<ajax:ToolkitScriptManager ID="tsm" runat="server" />

而不是 .TargetControlID = targetDDL.ID 我需要使用：

.TargetControlID = targetDDL.UniqueId
于 2011-11-10T20:00:52.537 回答