You are implementing a Windows Communication Foundation (WCF) service that uses Entity Framework to return POCO entities. The POCO entities do not need to track changes as the changes occur or support lazy loading of the related objects. You need to ensure that POCO entities can be easily serialized with the default DataContractSerializer.

What should you do?

WCF cannot directly serialize or deserialize proxies because the DataContractSerializer can serialize and deserialize only known types, and proxy types are not known types. When you need to serialize POCO entities, disable proxy creation or use the ProxyDataContractResolver class to serialize proxy objects as the original POCO entities. To disable proxy creation, set the ProxyCreationEnabled property to False.

Executing queries with the MergeOption query parameter set to NoTracking disables object state tracking. However, it does not prevent proxy creation to enable serialization.