Implementing multi-threading in workflows

Question

I'm aware a single workflow instance run in a single thread at a time. I've a workflow with two receive activities inside a pick activity. Message correlation is implemented to make sure the requests to both the activities should be routed to the same instance.

In the first receive branch I've a parallel activity with a delay activity in one branch. The parallel activity will complete either the delay is over or a flag is set to true.

When the parallel activity is waiting for the condition to meet how I can receive calls from the second receive activity? because the flag will be set to true only through through it's branch. I'm waiting for your suggestions or ideas.

Answer 1

Not quite sure what you are trying to achieve here.

If you have a Pick with 2 branched and both branches contain a Receive it will continue after you receive either of the 2 messages the 2 Receive activities are waiting for. The other will be canceled and not receive anything. The fact that one Receive is in a Parallel will not make a difference here. So unless this is on a loop you will not receive more than one WCF message in your workflow.

Answer 2

Check out my blog The Workflow Parallel Activity and Task Parallelism This will help you understand how WF works