[ServiceContract(SessionMode = SessionMode.Required)] public interface IOrderService {   [OperationContract(IsInitiating = true)]   void Init();   [OperationContract(IsInitiating = false, IsTerminating = false)]   void DoSomething();   [OperationContract(IsInitiating = false, IsTerminating = true)]   void Process(); } [ServiceBehavior(InstanceContextMode = InstanceContextMode.PerSession)] public class OrderService : IOrderService {   public void Init()   {     Console.WriteLine("Init...");   }   public void DoSomething()   {     Console.WriteLine("DoSomething...");   }   public void Process()   {     Console.WriteLine("Process...");   } } public class WcfTest {   public static void Test()   {     AppDomain.CreateDomain("Server").DoCallBack(delegate     {       ServiceHost host = new ServiceHost(typeof(OrderService),         new Uri("http://localhost:8080/MyService"));       host.AddServiceEndpoint(typeof(IOrderService), new WSHttpBinding(), "");       host.Open();     });     //-----------------------     IOrderService order = ChannelFactory<IOrderService>.CreateChannel(new WSHttpBinding(),       new EndpointAddress("http://localhost:8080/MyService"));     using (order as IDisposable)     {       order.Init();       order.DoSomething();       order.Process();     }   } }

IOrderService order = ChannelFactory<IOrderService>.CreateChannel(new WSHttpBinding(),   new EndpointAddress("http://localhost:8080/MyService")); using (order as IDisposable) {   //order.Init();   order.DoSomething();   order.Process(); }

未处理 System.InvalidOperationException   Message="The operation 'DoSomething' cannot be the first operation to be called because IsInitiating is false."

IOrderService order = ChannelFactory<IOrderService>.CreateChannel(new WSHttpBinding(),   new EndpointAddress("http://localhost:8080/MyService")); using (order as IDisposable) {   order.Init();   order.DoSomething();   order.Process();   order.DoSomething(); }

未处理 System.InvalidOperationException   Message="This channel cannot send any more messages because IsTerminating operation 'Process' has already been called."