WCF issue when upgrading from 3.5 to 4.0

Question

I recently updated the VS solution and projects from 3.5 to 4.0. After the conversion, I ran into a problem while sending object objects to WCF. When I submit an object that has no other child objects or any relationship with other objects, everything works fine ... the data is passed to WCF. But when the object has a child, I get the following error when calling my WCF service method:

EntityReference cannot be serialized. This type of object cannot be serialized when the RelationshipManager belongs to an object that does not implement IEntityWithRelationships.

Any idea what went wrong? I did not encounter any problems when using framework 3.5.

Answer 1

Perhaps this post on MSDN forums would be helpful?