Workflows are meant to coordinate systems and people, and that means communicating beyond the boundaries of the workflow instance itself. Communication is a key component of most workflows.
In the September issue of MSDN Magazine, Matt Milner takes you on a tour of the Windows Workflow Foundation (WF) communication architecture, sending data out of a workflow, and submitting data to running workflow instances.
As a bonus, you will also show you how to send data to a running workflow and get a response.
Don't forget to peruse Matt's sample code online, and be sure to check out the other workflow development information available in the MSDN Magazine archives and on the .NET Framework Developer Center.