I hurried from the key note to this session room to be able to video call home a moment. Luckily, my little daughter wasn’t sleeping yet (time difference is 8 hours), and she still recognized me as her ‘papa’.
In this picture I made while the session had just begun, you can see here walking to her room to go to bed.

Anyway, Ed Pinto gave a great talk about this subject:

As a reminder: what is WF?

New in WF 4.0 are Arguments and Variables.
Arguments: types that flow in and/or out of your Activity
Variables: you can store values in variables while running an Activity

Activities have user defined Variables for data storage:

Activities bind Arguments to in-scope Variables:

So here is an example of a Parallel Activity within the new WF 4.0 designer:

And a Sequence with a Try Catch:

A BIG new thing within WF is extended Correlation. You can now define CorrelationHandle’s and bind your SendMessage and ReceiveMessage to it:

Finally, Ed told us that Dublin will easy all this tremendously. I’ll visit a Dublin session later on.

When should you write WCF Services using Workflow? And what are the other WCF 4.0 improvements?

To me it’s interesting that that WF is not positioned as just a Human Workflow engine any more. It’s now very suitable to use in your messaging applications and make use of it’s parallelism, correlation and tracking!