Beginning Web Development, Silverlight, and ASP.NET AJAX

CHAPTER 9 ■ .NET 3.0: WINDOWS WORKFLOW FOUNDATION 223
Figure 9-11. Running the parameterized workflow with age greater than 100
Figure 9-12. Running the parameterized workflow with age less than 100
Out-of-the-Box Activities
If you followed along in the previous examples, you will have noticed that a variety of
out-of-the-box activities were available to you. You used two of them—the Code activity
and the IfElse activity. In addition to these, WF offers a few more:
Compensate: This is an activity that you can use in case of an error, and is used with
the FaultHandler activity. You use the Compensate activity to undo actions that have
already been performed, in a similar manner to a rollback in database transactions.
ConditionedActivityGroup (CAG): You use a CAG to specify a group of activities where
each one has its own criteria. When a condition for the group as a whole is met, execution
passes out of the group.
Delay: This activity allows you to put pauses of a specified duration into your
workflow.
EventDriven: This contains other activities to execute in response to an event firing.
FaultHandler: This allows you to handle errors. When an error occurs, you can direct
to a fault handler (like a Catch statement in code) and specify the actions to follow.
InvokeWebService: This is used to communicate with a web service via its proxy class.
A proxy class can be generated by the IDE when you make a reference to a web
service.
Parallel: This allows you to specify multiple parallel routes of execution, and will not
complete until all routes are complete.