Dependencies between Contract Inheritance and CallBack Inheritance in Indigo

Contract inheritance (via CLR interface inheritance) is pretty cool allowing you to support versioning and contract aggregation in WCF, the catch though is if you have a Duplex interface then the callback interface must follow the same hierarchy. So if your primary interface say is IMyInterface which inheritances from ISomeInterfaceOne and ISomeInterfaceTwo, then the callback interface also needs to have the same chain or you will get an InvalidContractException. Here is an example from MSDN:

[ServiceContract(CallbackContract = IACallback)]
interface IA : IB {}
interface IACallback : IBCallback {}
[ServiceContract(CallbackContract = IBCallback)]
interface IB {}
interface IBCallback {}

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Amit Bahree

This blog is my personal blog and while it does reflect my experiences in my professional life, this is just my thoughts. Most of the entries are technical though sometimes they can vary from the wacky to even political – however that is quite rare. Quite often, I have been asked what’s up with the “gibberish” and the funny title of the blog? Some people even going the extra step to say that, this is a virus that infected their system (ahem) well. [:D] It actually is quite simple, and if you have still not figured out then check out this link – whats in a name?

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