Error when all context menus are not visible in UI for ASP.NET AJAX TreeView

Doron Yaacoby

4 posts

Member since:
Mar 2009

Posted 21 May 2009 Link to this post

Hi,
I have a page with a tree-view and two context menus that are not visible by default. When I select an item in the tree, I get a javascript error: 'Telerik.Web.UI.RadContextMenu is null or not an object'. I've fixed it for now by adding a "dummy" context-menu with no items in it (but with the Visible property set to 'true'), but I would like to know if there is a better solution.

Thanks.

Shinu

17764 posts

Member since:
Mar 2007

Posted 26 May 2009 Link to this post

Hi Doron,

I guess you want not to show the RadContextMneu for some nodes of treeview. If so, better way to accomplish this is by canceling the event in OnClientContextMenuShowing method after checking the node that the context menu is being opened for.

ASPX:

    
            <telerik:radtreeview id="RadTreeView1" runat="server" OnClientContextMenuShowing="ClientContextMenuShowing"> 
        
            <ContextMenus> 
        
            <telerik:RadTreeViewContextMenu ID="ContextMenu"> 
        
                <Items> 
        
                    <telerik:RadMenuItem Text="Copy" Value="Copy"></telerik:RadMenuItem> 
        
                    <telerik:RadMenuItem Text="Edit" Value="Edit"></telerik:RadMenuItem> 
        
                </Items> 
        
            </telerik:RadTreeViewContextMenu> 
        
            </ContextMenus> 
        
            <Nodes> 
        
            <telerik:RadTreeNode runat="server" Text="Peripherals"> 
        
            <Nodes> 
        
                <telerik:RadTreeNode runat="server" Text="Printers"></telerik:RadTreeNode> 
        
                <telerik:RadTreeNode runat="server" Text="Scanners"></telerik:RadTreeNode> 
        
            </Nodes> 
        
            </telerik:RadTreeNode> 
        
            </Nodes> 
        
            </telerik:radtreeview>

JavaScript:

    
            <script type="text/javascript"> 
        
            function ClientContextMenuShowing(sender, eventArgs) 
        
            { 
        
             var node = eventArgs.get_node();    
        
             var menu = eventArgs.get_menu();    
        
             if (node.get_text() == "Printers") 
        
              {        
        
                  eventArgs.set_cancel(true); 
        
              } 
        
            } 
        
            </script>

Note: eventArgs.set_cancel(true) will cancel the event and the contextmenu is not shown.

Thanks,
Shinu.

Veselin Vasilev

Admin

2992 posts

Posted 26 May 2009 Link to this post

Hi Doron,

in addition, instead of setting the Visible property to False of the context menus please use

RadTreeView1.ContextMenus.Clear();

Regards,
Veselin Vasilev
the Telerik team

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