DataContract serialization throw an Security exception

I am trying to use DataContractSerialization on WPF and WP7. A开发者_开发百科ll things are good on WPF but not on WP7. When I tryed to serialize an object on wp7, I received an unknown security exception. Please view the attached source code and help me.

Source code (mediafire)

Thanks.

I had the same issue.

In my scenario, I was trying to serialize a nested class.

I had to remove the nesting and define the class as public, and then it worked.