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Tree View Events are not firing.

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Stephen Holder
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Stephen Holder asked on 25 May 2010, 08:11 PM
SilverLight version 4
Internet Explorer version 8
Windows Server 2008

I had regular SilverLight TreeView controls.  I replace one of them with the Telerik TreeView control.  This one in particular had no event hook-ups.  I wanted to disable the expanding and collapsing of nodes so that the control will always stay expanded.  I hooked into two events as the coded example:

<telerik:RadTreeView x:Name="tvMDocs" PreviewExpanded="tvMDocs_PreviewExpanded" PreviewCollapsed="tvMDocs_PreviewCollapsed" /> 


The code behind is as the following:

 
        private void tvMDocs_PreviewExpanded(object sender, Telerik.Windows.RadRoutedEventArgs e)  
        {  
            e.Handled = true;  
        }  
 
        private void tvMDocs_PreviewCollapsed(object sender, Telerik.Windows.RadRoutedEventArgs e)  
        {  
            e.Handled = true;  
        }  
 

I have the break points set to stop at the "e.Handled = true".  I am assuming that the events are not firing because it does not stop at these points. Any suggestions to why this isn't working would be greatly appreciated.

Steve

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Miroslav
Telerik team
answered on 26 May 2010, 02:02 PM
Hi Stephen Holder,

This is indeed unexpected. Do you mean that the user can still collapse an item?

Is it possible that handling the PreviewExpanded event cancels out a possible ExpandAll() call?

You can have a look at the attached project where this seems to work. Am I missing something?

Kind regards,
Miroslav
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Stephen Holder
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answered on 26 May 2010, 02:56 PM

Miroslav,

 


    Yes, your little project works fine.  I can set a break point at the "e.Handled = true;" and the debugger does stop at the break point.
This is very straight forward code and almost identical to my code except that I do not have the TreeViewItems hard coded in the xaml.  The treeview items are built in code behind using the directory structure and files from SharePoint sites.  I set each item's "IsExpanded" as they are added to the tree.  The other difference is that the treeviews are in two seperate RadTiles which shouldn't make a difference on the firing of the events.  As I said in my original question, I am fairly sure that the PreviewCollasped and PreviewExpanded are not fiiring back to my code behind because they don't stop at the breakpoints in my code.
    I am going to try an experiment by making a small hard coded Treeview as per your sample code, within my page and see if that works. My concern is that perhaps the code I am using to load my Treeview is not loading it correctly even though it displays correctly and thus the events don't fire.  I will let you know how this goes.

Steve

 

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Stephen Holder
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answered on 26 May 2010, 06:47 PM
Miroslav,

    I guess I am at square one.  I can make a new tile and cut and paste your sample xaml with an event code-behind function and
it works.  I think I am probably going to have to recode the recursive logic that I was using to fill the SilverLight 4 Treeview Control
because there must be some difference in how I should be filling it.  I will look on your site at sample code and try to rework this.
I will let you know how I solve it but it may take me a while.

Steve
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Miroslav
Telerik team
answered on 27 May 2010, 08:17 AM
Hello Stephen Holder,

This is indeed strange. Can you send us a sample project where the events are not fired?

If you will be displaying a file-folder system, it may be best to databind the TreeView and use virtualization since it will scale much better. I tried the always-expand in this scenario as well, you can check out the attached project.

Which version of the controls are you using?

Greetings,
Miroslav
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Miroslav
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