Multiple controls with the same ID

[Neil N]

I'm getting an " Multiple controls with the same ID 'approvalsPending' were found" error with the Q1 2009 tabstrip when clicking a tab with subtabs, clicking another tab, and then clicking the first tab.

Tabstrip definition:

<telerik:RadTabStrip ID="RadTabStrip1" runat="server" OnClientTabSelecting="onTabSelecting" MultiPageID="RadMultiPage1" SelectedIndex="0" Skin="OESskin" EnableEmbeddedSkins="False">
    <Tabs>
        <telerik:RadTab runat="server" Text="Confirmation" Value="confirmation" />
         <telerik:RadTab runat="server" Text="Contact" Value="contact" />
         <telerik:RadTab runat="server" Text="RA Requests" Value="raRequests" >
         <Tabs>
            <telerik:RadTab runat="server" Text="Remitters List" Value="chooseRemitters" />
            <telerik:RadTab runat="server" Text="Stewards List" Value="chooseStewards" />
         </Tabs>
        </telerik:RadTab>
         <telerik:RadTab runat="server" Text="Approvals" Value="approvals">
         <Tabs>
            <telerik:RadTab runat="server" Text="Pending Approvals" Value="approvalsPending" />
            <telerik:RadTab runat="server" Text="Requested Approvals" Value="approvalsRequested" />
         </Tabs>
        </telerik:RadTab>
         <telerik:RadTab runat="server" Text="Approved RA's" Value="approved" />
    </Tabs>
</telerik:RadTabStrip >
<br />
<telerik:RadMultiPage ID="RadMultiPage1" runat="server" SelectedIndex="0" CssClass="multiPage">
</telerik:RadMultiPage>

Code behind:

    Protected Sub RadMultiPage1_PageViewCreated(ByVal sender As Object, ByVal e As RadMultiPageEventArgs) Handles RadMultiPage1.PageViewCreated
        Dim userControlName As String = "tabpages\" & e.PageView.ID & ".ascx"
        Dim userControl As Control = Page.LoadControl(userControlName)
        userControl.ID = e.PageView.ID & "_userControl"
        e.PageView.Controls.Add(userControl)

        If (e.PageView.ID <> "chooseRemitters" Or Session("chooseRemitters") = 0) And (e.PageView.ID <> "approvalsPending" Or Session("approvalsPending") = 0) Then
            CType(userControl, tabpage).loadTab()
        Else
            CType(userControl, tabpage).reloadTab()
        End If
    End Sub

    Private Sub AddPageView(ByVal tab As RadTab)
        Dim pageView As RadPageView = New RadPageView
        pageView.ID = tab.Value
        RadMultiPage1.PageViews.Add(pageView)
        tab.PageViewID = pageView.ID
    End Sub

    Protected Sub RadTabStrip1_TabClick(ByVal sender As Object, ByVal e As RadTabStripEventArgs) Handles RadTabStrip1.TabClick
        Dim clickedTab As New RadTab

        If e.Tab.Value = "raRequests" Then
            If RadTabStrip1.FindTabByValue("chooseRemitters").Visible = True Then
                clickedTab = RadTabStrip1.FindTabByValue("chooseRemitters")
            Else
                clickedTab = RadTabStrip1.FindTabByValue("chooseStewards")
            End If
        ElseIf e.Tab.Value = "approvals" Then
            clickedTab = RadTabStrip1.FindTabByValue("approvalsPending")
        Else
            clickedTab = e.Tab
        End If

        AddPageView(clickedTab)
        clickedTab.PageView.Selected = True
    End Sub

I've tried commenting out userControl.ID = e.PageView.ID & "_userControl" and pageView.ID = tab.Value but that didn't help.

STACKTRACE:    at System.Web.UI.Control.FillNamedControlsTable(Control namingContainer, ControlCollection controls)

   at System.Web.UI.Control.FillNamedControlsTable(Control namingContainer, ControlCollection controls)

   at System.Web.UI.Control.FillNamedControlsTable(Control namingContainer, ControlCollection controls)

   at System.Web.UI.Control.EnsureNamedControlsTable()

   at System.Web.UI.Control.FindControl(String id, Int32 pathOffset)

   at System.Web.UI.Control.FindControl(String id)

   at Telerik.Web.UI.RadTabStrip.get_MultiPage()

   at Telerik.Web.UI.RadTab.get_PageView()

   at agreements.RadTabStrip1_TabClick(Object sender, RadTabStripEventArgs e) in D:\My Documents\Visual Studio 2005\WebSites\OES Reporting\agreements.aspx.vb:line 59

   at Telerik.Web.UI.RadTabStrip.RaiseEvent(Object eventKey, RadTabStripEventArgs e)

   at Telerik.Web.UI.RadTabStrip.OnTabClick(RadTabStripEventArgs e)

   at Telerik.Web.UI.RadTabStrip.RaisePostBackEvent(String eventArgument)

   at Telerik.Web.UI.RadTabStrip.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument)

   at System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument)

   at System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData)

   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

Line 59 is: clickedTab.PageView.Selected = True

[Paul]

Hi Neil,

This can occur only if some of your controls' IDs are duplicate (PageView id or user control id) or if a pageview/UserControl is added twice on the page. Still, It will be best if you can open a support ticket and send us a simple running project (incl. your custom skin, CSS, images, DB backup if needed and so on) demonstrating the problem (and step-by-step instructions on doing so). In that way we can reproduce and pinpoint the problems you're facing on our side, understand the logic of your application and provide a solution.

Regards,
Paul
the Telerik team

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[Neil N]

Got a fix, recording it here if anyone else has the same problem (since I copied the code from a Telerik demo):

    Private Sub AddPageView(ByVal tab As RadTab)
        Dim pageView As RadPageView = New RadPageView
        pageView.ID = tab.Value
        If IsNothing(RadMultiPage1.FindPageViewByID(tab.Value)) Then  'add page view only if it not already there
            RadMultiPage1.PageViews.Add(pageView)
        End If
        tab.PageViewID = pageView.ID
    End Sub