How to Define method in DataContract class

I want to add some method in class that i开发者_开发知识库 define as a 'DataContract' class. I need that the client will call those method in some cases.

Is it possible? How can i do it ?

Thanks for any help.

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If you mean that you want to add a service call to a DataContract then that is not possible. If you want to add some helper methods to the data contract and you want to make those available to the client as well then you can do that if you are also in charge of the client code or you are willing to share the library containing the data contract class with the clients.