如何使用WCF调用从客户端Windows Phone 8.0 silverlight返回对象的方法

I have implemented a library WCF service , and I have tested it in the WCF test client and it works perfectly, but when I've tried to call the methods from the hosting application (windows phone 8.0 silverlight), All the methods were(void), they works but they return nothing !I have implemented a library WCF service , and