InvalidCastException using RadComboBox

[Lisa Smith]

I'm randomly getting the error below when clicking on a RadComboBox. I upgraded to version 2010.3.1314.1040 hoping that would solve the problem, but it did not. Any ideas?

Webpage error details

User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; InfoPath.3; .NET4.0C; .NET4.0E; MS-RTC LM 8)
Timestamp: Tue, 12 Apr 2011 19:12:24 UTC

Message: Unhandled Error in Silverlight Application
Code: 4004   
Category: ManagedRuntimeError      
Message: System.InvalidCastException: Specified cast is not valid.
   at MS.Internal.XcpImports.MethodEx(IntPtr ptr, String name, CValue[] cvData)
   at MS.Internal.XcpImports.MethodEx(DependencyObject obj, String name)
   at System.Windows.UIElement.UpdateLayout()
   at Telerik.Windows.Controls.PopupWrapper.AdjustPopupLocation()
   at Telerik.Windows.Controls.RadComboBox.AdjustPopupLocation()
   at Telerik.Windows.Controls.RadComboBox.UpdateItemsVisibility(Boolean showAll, List`1 matchIndices)
   at Telerik.Windows.Controls.RadComboBox.DropDownPopupOpened(Object sender, EventArgs e)
   at MS.Internal.CoreInvokeHandler.InvokeEventHandler(Int32 typeIndex, Delegate handlerDelegate, Object sender, Object args)
   at MS.Internal.JoltHelper.FireEvent(IntPtr unmanagedObj, IntPtr unmanagedObjArgs, Int32 argsTypeIndex, Int32 actualArgsTypeIndex, String eventName)    

Line: 58
Char: 17
Code: 0 

[Gonzalo]

Just a thought. Make sure when setting make sure that all your references are pointing out to the new controls. I have had problems when referencing different versions of dlls by mistake. In other words, check you references and make sure that all telerik controls being used are of the same series and not mixed...

Best wishes,

G

[Valeri Hristov]

Hi Lisa,

We received similar bug reports in the past, but we never managed to get a project that could be used to observe the problem. If you could send us a simple application that we can debug we will reply with a solution as soon as possible.

Greetings,
Valeri Hristov
the Telerik team