I upgraded to your current release (2010.2 812) today and my comboboxes are broken in my application. As soon as I select a item i get this error

Attempt by method 'System.Linq.Expressions.Expression.CreateLambda(System.Type, System.Linq.Expressions.Expression, System.String, Boolean, System.Collections.ObjectModel.ReadOnlyCollection`1<System.Linq.Expressions.ParameterExpression>)' to access method 'System.Linq.Expressions.Expression`1<System.Func`2<FTSilverControls.FTActivityDialog+FTListItem,FTSilverControls.FTActivityDialog+FTListItem>>.Create(System.Linq.Expressions.Expression, System.String, Boolean, System.Collections.ObjectModel.ReadOnlyCollection`1<System.Linq.Expressions.ParameterExpression>)' failed.

This worked fine in previous builds for the past 1.5 years.

I tracked down the issue....my class FTListItem was marked internal as was its constructors. When I changed those to public everything started to work again. However, this is really not an ideal workaround. Any thoughts??

Hello Matt Fraser,

Thank you for contacting us.

We made some optimizations of RadComboBox. This problem is caused by limitation of the framework. You cannot use LINQ queries to internal types. We suggest you to change the accessor of your class from internal to protected.  

I hope this helps. Please do not hesitate to contact us if you require any further information.

Best wishes,
George
the Telerik team

Bonjour,

I have the same issue but unfortunately my class are not inner classes so i cannot declare them as protected, do you have another way to make it work?

If you don't have any other way can you provide a style for the built in ComboBox of silverlight to look the same way than your combobox, because it works fine with the system combobox.so it could be a good alternative.

Hello Yann,

Could you please send us a simple application that demonstrates your usage of internal classes with RadComboBox? I wasn't able to make the standard ComboBox to work in scenario where RadComboBox doesn't...

Regards,
Valeri Hristov
the Telerik team

The ticket is submited you just need to uncoment your combobox in the main page to reproduce the bug

Ticket # 490378

Hi,

Thank you for the provided application, I appreciate your effort. We were able to reproduce and fix the problem, the upcoming internal build next week will work without problems in your scenario.

Your points have been updated.

Best wishes,
Valeri Hristov
the Telerik team