ArgumentException when placing RadTreeViewItem in EditMode

[Paul Brun]

I have defined a DataItemTempate for my RadTreeItem in the following manner:

<DataTemplate x:Key="EditTreeViewTemplate">
       <StackPanel Orientation="Horizontal">
           <UserControl Content="{Binding IconControl}"/>
           <TextBox Text="{Binding Rename, Mode=TwoWay}" Margin="5" />
       </StackPanel>
   </DataTemplate>

I pass the EditTreeViewTemplate into the ItemEditTemplate property of the RadTreeView. Both bindings work because a simple format used in my HierarchicalDataTemplate works without a problem. The UserControl hosts a Icon created in Blend and represented in XAML form.

If I remove the UserControl, the edit works without a problem. Keep it in there, IE crashes with a ManagedRunTimeError 4004

Thoughts on getting this to work.

[Miroslav]

Hi Paul Brun,

This exception normally comes up when a visual element is placed in the visual tree twice, it is common when visual elements are databound.

The problem here is a bug in Silverlight where a visual element will not be removed from its parent when the binding is removed / reset.

Several suggestions:
- Use a ContentPresenter instead of a UserControl
then:
1. Remove the visual element (IconControl)  from its parent (ContentPresenter) in the properties getter. Be careful not to get the same property from other code.
2. Bind to a non-visual value and use a ValueConverter to create and initialize the control. This may be a good approach since its lazy and the control is not needed most of the time.

Kind regards,
Miroslav
the Telerik team

[Paul Brun]

you don't by chance happen to have a quick example that shows what you are talking about, do you? Just trying to piece together a solution that will make this work and this problem is widely reported too...

Paul

[Tina Stancheva]

Hi Paul Brun,

I attached a sample project illustrating how to use a visual element in an ItemEditTemplate. The example demonstrates three different approaches so that you  can choose the best suited for your scenario.

Take a look at it and let us know if you need more info.

Sincerely yours,
Tina Stancheva
the Telerik team