WCF Data Services June CTP: LINQ Improvements and Properties on Derived Types
The WCF Data Services June 2011 CTP includes Any/All operators for LINQ, support for properties and inheritance on derived types, and an OData serializer/deserializer. This release targets .NET 4 and Silverlight 4; support for Windows 7 Phone is not yet included.
The Any and All set operators were previously unsupported in WCF Data Services, but they have been added in the June CTP.
Properties on Derived Types
Previous versions of WCF Data Services supported relationships and inheritance, but would throw an exception if derived types had relationships with other types. According to Microsoft, "WCF Data Services now supports both exposing and consuming models which have properties (primitive, complex & navigation) defined on subtypes of the the base type associated with the set."
WCF Data Services supports serialization for non-binary Atom and JSON formats. This release includes an OData serializer and deserializer for use in client or server stacks.
The WCF Data Services team notes that the first two items are among the top three requested new features. The third is support for the Enum data type, which was recently added to the Entity Framework as part of the June CTP. This would seem to indicate that Enum support in WCF will happen as well, though nothing has been officially announced.