NullValue Exception

[Philippe]

Hi,

I use ScheduleView in a WPF Application and I've got a problem running it on a Tablet PC : When the application starts, an exception is thrown indefinitely :

System.ArgumentNullException: La valeur ne peut pas être null.
Nom du paramètre : collection
   à System.ThrowHelper.ThrowArgumentNullException(ExceptionArgument argument)
   à System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   à Telerik.Windows.Automation.Peers.RadDateTimePickerAutomationPeer.GetChildrenCore()
   à System.Windows.Automation.Peers.AutomationPeer.EnsureChildren()
   à System.Windows.Automation.Peers.AutomationPeer.UpdateChildren()
   à System.Windows.Automation.Peers.AutomationPeer.UpdateSubtree()
   à System.Windows.Automation.Peers.AutomationPeer.UpdateSubtree()
   à System.Windows.Automation.Peers.AutomationPeer.UpdateSubtree()
   à System.Windows.Automation.Peers.AutomationPeer.UpdateSubtree()
   à System.Windows.Automation.Peers.AutomationPeer.UpdateSubtree()
   à System.Windows.Automation.Peers.AutomationPeer.UpdateSubtree()
   à System.Windows.Automation.Peers.AutomationPeer.UpdateSubtree()
   à System.Windows.ContextLayoutManager.fireAutomationEvents()
   à System.Windows.ContextLayoutManager.UpdateLayout()
   à System.Windows.ContextLayoutManager.UpdateLayoutCallback(Object arg)
   à System.Windows.Media.MediaContext.InvokeOnRenderCallback.DoWork()
   à System.Windows.Media.MediaContext.FireInvokeOnRenderCallbacks()
   à System.Windows.Media.MediaContext.RenderMessageHandlerCore(Object resizedCompositionTarget)
   à System.Windows.Media.MediaContext.RenderMessageHandler(Object resizedCompositionTarget)
   à System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter)
   à System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler)

I use the 2012.2.0912.35 version of telerik components on Framework 3.5.

Can you help me with this ?

Thanks
Philippe

[Ventzi]

Hi Philippe,

We are not aware of such bug. We've tried to reproduce the problem, but unfortunately we couldn't. Please update your version of RadControls to the latest available and give it a try. If you still observe the same issue, please try to create a sample project which we could investigate further.

Kind regards,
Ventzi
the Telerik team

[Philippe]

Hi,

We already use the latest available version for framework 3.5..
Unfortunately, we are not able to reproduce the problem, it happen only on a little number of devices (tablet PC)
I was just hoping that the stack trace could lead you to the key of the problem
(AutomationPeer.EnsureChildren() / RadDateTimePickerAutomationPeer.GetChildrenCore())

regards

[Ventzi]

Hi Philippe,

I didn't notice that you are using the Telerik controls for framework 3.5. There is indeed a bug in the RadDateTimePickerAutomationPeer class for .NET 3.5, but since Q3 2012 we don't provide any support or bug fixing for .NET 3.5 anymore. You could read more about it in this blog post. 

We strongly suggest you to upgrade your framework version to 4.0 or above where this issue is already fixed.
According to the issue itself - may be these few devices where the issue occurs having automation clients running like screen reader, tabtip in tablet etc. Shutting down these apps could workaround this problem.

We are sorry for the inconvenience caused.

Regards,
Ventzi
the Telerik team