how to let WCF service to send messages to the client without calling its method from the service?

Question

Im new to WCF and what i know till now that i can use a method from WCF service and it returns some value back, but i was wondering if i used a and i want to send a message like "Job Complete" to the client after it got finished, how would i do that? 并且想向客户端发送“ Job Complete”之类的消息完成后，我该怎么办？
Should i use AutoResetEvent and wait for the backgroundworker until completes then resetEvent.Set() to let the method on the main thread to return the message?
i need that thread not to get busy, it should be ready for any other commands i request from the client. so any ideas?

Answer 1

I've figured it out, well i couldn't send message back from service without calling the method but when i changed the attributes of the service behavior from ConcurrencyMode = ConcurrencyMode.Single to ConcurrencyMode = ConcurrencyMode.Multiple it went multithreaded and the result :
the method runs in a new thread because of this attribute and i can send other request while that thread is working and when it finishs it returns me the message/result.

[ServiceBehavior(ConcurrencyMode = ConcurrencyMode.Multiple, InstanceContextMode = InstanceContextMode.PerSession)]
public class FileManagerService : IFileManager