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MouseOver tab selection

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TabStrip
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Tomica
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Tomica asked on 27 Mar 2014, 06:52 PM
I am attempting to add mouseover activation of tabs, per the following article:

http://www.telerik.com/help/aspnet-ajax/tabstrip-change-tabs-mouseover.html

I copied the code, the page loads without error, and the tabs change as intended.

However I get "Line: 75 Error: Unable to get property 'selectParents' of undefined or null reference" as soon as the mouse moves out of the tabstrip control..

Running Win 8.1 with I.E. 11 when the error occurs.

No error with Firefox.

I would like to know what this error is and how I might adjust the code to prevent or ignore.


<%@ Page Language="VB" AutoEventWireup="false" CodeFile="tabstrip_mouseover.aspx.vb" Inherits="tabstrip_mouseover" %>
 
<!DOCTYPE html>
 
<head runat="server">
    <title></title>
</head>
<body>
<form id="form1" runat="server">
   <asp:ScriptManager ID="ScriptManager1" runat="server" />
   <script type="text/javascript" language="javascript">
       function SelectMyTab(sender, args) {
           var multiPageID = sender.get_multiPageID();
           sender.set_multiPageID(null);
           args.get_tab().select();
           sender.set_multiPageID(multiPageID);
       }
 
       function UnSelectMyTab(e) {
           var tabStrip = $find('<%= RadTabStrip1.ClientID%>');
       //Find the element which the mouse is over
       var destElement = e.relatedTarget || e.toElement;
       if ($telerik.isDescendant(tabStrip.get_element(), destElement))
           return;
       var initialTab = tabStrip.findTabByText("<%= MyTab %>");
       //initialTab.unselect();
       initialTab.selectParents();
   }
   </script>
   <telerik:RadTabStrip ID="RadTabStrip1" runat="server" UnSelectChildren="true" OnClientMouseOver="SelectMyTab" ClickSelectedTab="True" AutoPostBack="True" onmouseout="UnSelectMyTab(event)" SelectedIndex="0" Skin="Outlook" MultiPageID="RadMultiPage1">
       <Tabs>
           <telerik:RadTab ID="Tab1" runat="server" Text="Root Tab 1">
               <Tabs>
                   <telerik:RadTab ID="Tab2" runat="server" Text="Child Tab 1.1" PageViewID="PageView1">
                   </telerik:RadTab>
                   <telerik:RadTab ID="Tab3" runat="server" Text="Child Tab 1.2" PageViewID="PageView2">
                   </telerik:RadTab>
               </Tabs>
           </telerik:RadTab>
           <telerik:RadTab ID="Tab4" runat="server" Text="Root Tab 2">
               <Tabs>
                   <telerik:RadTab ID="Tab5" runat="server" Text="Child Tab 2.1" PageViewID="PageView3">
                   </telerik:RadTab>
                   <telerik:RadTab ID="Tab6" runat="server" Text="Child Tab 2.2" PageViewID="PageView4">
                   </telerik:RadTab>
                   <telerik:RadTab ID="Tab7" runat="server" Text="Child Tab 2.3" PageViewID="PageView5">
                   </telerik:RadTab>
               </Tabs>
           </telerik:RadTab>
           <telerik:RadTab ID="Tab8" runat="server" Text="Root Tab 3">
               <Tabs>
                   <telerik:RadTab ID="Tab9" runat="server" Text="Child Tab 3.1" PageViewID="PageView6">
                   </telerik:RadTab>
               </Tabs>
           </telerik:RadTab>
       </Tabs>
   </telerik:RadTabStrip>
   <telerik:RadMultiPage ID="RadMultiPage1" runat="server" Height="454px" Width="737px">
       <telerik:RadPageView ID="PageView1" runat="server">
           Child Tab 1.1</telerik:RadPageView>
       <telerik:RadPageView ID="PageView2" runat="server" Width="100%">
           Child Tab 1.2</telerik:RadPageView>
       <telerik:RadPageView ID="PageView3" runat="server" Width="100%">
           Child Tab 2.1</telerik:RadPageView>
       <telerik:RadPageView ID="PageView4" runat="server" Width="100%">
           Child Tab 2.2</telerik:RadPageView>
       <telerik:RadPageView ID="PageView5" runat="server" Width="100%">
           Child Tab 2.3</telerik:RadPageView>
       <telerik:RadPageView ID="PageView6" runat="server" Width="100%">
           Child Tab 3.1</telerik:RadPageView>
   </telerik:RadMultiPage>
</form>
</body>
</html>


Imports System
Imports System.Data
Imports System.Data.SqlClient
Imports System.Configuration
Imports System.Collections
Imports System.Web
Imports System.Web.Security
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Web.UI.WebControls.WebParts
Imports System.Web.UI.HtmlControls
Imports Telerik.Web.UI
 
 
 
Partial Public Class tabstrip_mouseover
    Inherits System.Web.UI.Page
    Protected MyTab As String
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
        MyTab = RadTabStrip1.InnermostSelectedTab.Text
    End Sub
End Class







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Tomica
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answered on 27 Mar 2014, 07:17 PM
Update: the error seems to be isolated to my development environment, which is Visual Studio 2013 and IIS Express, i.e. pretty standard setup.

I added a try / catch block on the troublesome un-select code, but I do not know what I might be losing by doing so.

Perhaps it is not necessary, my experience with server-side programming in VB is that selecting one tab automatically un-selects the previous selection. Unsure of every step I take with client-side <g>
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Nencho
Telerik team
answered on 01 Apr 2014, 11:50 AM
Hello Thomas,

I tried to replicate the described issue, following the provided steps for reproduction, but to no avail. I was unable to observe any error, when the mouse moves out of the RadTabStrip control. Could you specify which version of our controls are you currently using?

Regards,
Nencho
Telerik
 

Build cross-platform mobile apps using Visual Studio and .NET. Register for the online webinar on 03/27/2014, 11:00AM US ET.. Seats are limited.

 
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Tomica
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answered on 06 Apr 2014, 11:11 PM
Error only occurs on IIS Express in development environment.

I have not been able to duplicate it elsewhere, so let's just "assume" the problem lies within IIS and can be safely ignored.
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Tomica
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Tomica
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Nencho
Telerik team
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