If you don’t call the “Open” method first, the proxy would be opened internally when the first call is made on the proxy. This is called auto-open.
Why? When the first message is sent through the auto-opened proxy, it will cause the proxy to be opened automatically. You can use .NET Reflector to open the method System.ServiceModel.Channels.ServiceChannel.Call and see the following code:
Code:
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| if (!this.explicitlyOpened)
{
this.EnsureDisplayUI();
this.EnsureOpened(rpc.TimeoutHelper.RemainingTime());
} |
When you drill down into EnsureOpened, you will see that it calls CallOnceManager.CallOnce. For non-first calls, you would hit SyncWait.Wait which waits for the first request to complete. This mechanism is to ensure that all requests wait for the proxy to be opened and it also ensures the correct execution order. Thus all requests are serialized into a single execution sequence until all requests are drained out from the queue. This is not a desired behavior in most cases.
To avoid such “serializing” artifact, the best practice is to open the proxy explicitly as above. Once you get to this point, you will be able to share the same proxy object among multiple threads.
