Error occurs with ListBox in RadDropDownButton as DropDownContent

[Wenhao]

Hello Telerik:

This coule be a really strange issue. I copied the following code from within your demo application, and I just created a UserControl to hold this as below:

    <Grid x:Name="LayoutRoot" Background="White"><br>        <telerik:RadDropDownButton Width="200" Height="24"><br>            <telerik:RadDropDownButton.DropDownContent><br>                <ListBox SelectionChanged="Selector_OnSelectionChanged" Height="200" Width="200" /><br>            </telerik:RadDropDownButton.DropDownContent><br>        </telerik:RadDropDownButton><br>    </Grid>

MainPage.xaml:

    <Grid x:Name="LayoutRoot" Background="White">

        <!-- Works right! -->
        <slvs2013Test:SilverlightControl1 />
        
        
        <!-- Won't work, exception throws -->
        <!--<slvs2013Test:Class1 />-->
    </Grid>


Actually, the event handler "Selector_OnSelectionChanged" does nothing but an empty block.

When I add this UserControl on the page, everything works ok~ However, I create another class which JUST inherits from this UserControl. Sadlly, it does NOT work any more. I add it onto the page, but an exception occurs everytime, that could makes me crazy.

I attached the source code in this thread, PLEASE HELP!!!!!

Wenhao

[Boris]

Hello Wenhao,

We managed to reproduce this issue and it is also reproducible if you remove the RadDropDownButton and leave only the ListBox. This appears to be a framework limitation and the XAML parser cannot handle it. You can see this problem reported here and here.
However, we strongly believe that inheriting a UserControl is considered a bad practice and it should avoided.

Regards,
Boris Penev
Telerik