Is WCF ClientBase thread safe?

Question

I have implemented ClientBase to use WCF to connect to a service. I'm then calling a method on the channel to communicate with the service.

base.Channel.CalculateSomething(); 

Is this call thread safe or should I lock around it when running multiple threads?

Thanks

Answer 1

The follow-up comments on the answers here had me uncertain as well, so I did some more digging. Here is some solid evidence that ClientBase<T> is thread-safe - this blog post discusses how to make a WCF service perform properly in the presence of a single client proxy being used by multiple threads simultaneously (the bold emphasis is in the original):

... However, there is a scenario where setting ConcurrencyMode to Multiple on a PerCall service can increase throughput to your service if the following conditions apply:

1. The client is multi-threaded and is making calls to your service from multiple threads using the same proxy.

2. The binding between the client and the service is a binding that has session (for example, netTcpBinding, wsHttpBinding w/Reliable Session, netNamedPipeBinding, etc.).

Also, the evidence in this post seems to contradict Brian's additional remark that WCF serializes any multi-threaded requests. The post shows multiple requests from a single client running simultaneously - if ConcurrencyMode.Multiple and InstanceContextMode.PerCall are used.

There is some additional discussion here regarding the performance implications of this approach as well as some alternatives.