Value cannot be null

[Juliana]

Hi,
After installing SL 5 RC I'm  getting an exception at runtime:

{System.ArgumentNullException: Value cannot be null.
Parameter name: element
   at MS.Internal.XcpImports.ItemsControl_GetItemsOwner(DependencyObject element)
   at System.Windows.Controls.ItemsControl.ItemsControlFromItemContainer(DependencyObject container)
   at Telerik.Windows.Controls.ItemsControl.ItemsControlFromItemContainer(DependencyObject container)
   at Telerik.Windows.Controls.ListBoxItem.get_ParentSelector()
   at Telerik.Windows.Controls.RadComboBoxItem.get_ParentComboBox()
   at Telerik.Windows.Controls.RadComboBoxItem.OnContentChanged(Object oldContent, Object newContent)
   at System.Windows.Controls.ContentControl.OnContentChanged(IntPtr nativeTarget, CValue& oldContentValue, CValue& newContentValue)}

RadComboBox is declared like

 <telerik:RadComboBox x:Name="cmbFilter"  VerticalAlignment="Center" FontWeight="Bold"
                                                 Background="Transparent" BorderThickness="0"
                                                 SelectionChanged="cmbFilter_SelectionChanged">
                                <telerik:RadComboBox.Items>
                                    <telerik:RadComboBoxItem Content="Guest Name" IsSelected="True"/>
                                    <telerik:RadComboBoxItem Content="File Name"/>
                                </telerik:RadComboBox.Items>
                            </telerik:RadComboBox>
Content property is underlined.

But control type doesn't matter. I get such an exception when trying to set Content property of RadTabItem as well.
Target framework for the project is SL4. Telerik Controls version 2011.2.725.1040

How can it be fixed?
Juliana

[Kiril Stanoev]

Hello Juliana,

We are currently testing our controls against the Silverlight 5 RC. There are some issues that we found and some of them are major like the one in the thread you send. We will definitely work on resolving them, but in the moment I can't give you a specific time frame when there will be stable version compatible with Silverlight RC. But I can assure you that we are tightly following Microsoft releases and will try to provide compatible controls as soon as possible.

Don't hesitate to contact us if you have further questions

Greetings,
Kiril Stanoev
the Telerik team

[Juliana]

Hello Kiril,
Thanks for the reply. Looking forward to stable update.
Juliana

[Erlend]

Hi, 

Is there any new updates for this issue?
Is there a known workaround?
Have you been able to get a time frame for a working update for telerik controls for SL5 RC?

Thanks and Regards, 

[Juliana]

Hi,
this thread is more useful, but I think you are not going to like the answer
http://www.telerik.com/community/forums/silverlight/general-discussions/silverlight-5-0-rc.aspx

[Øivind]

Comment / possible workaround:

We experience the same problems with the RadOutlookBar and RadTabControl in the RC.
I've however found that these controls only fail if you specify the items in xaml - if you bind the controls to an ItemsSource (dynamically populating the items), they don't fail (at least not for me).

/ Øivind Solberg