The StateActivity represents a State in a StateMachineWorkflowActivity. State activities could contain one or more EventDrivenActivity, or StateActivity classes, one StateInitializationActivity class, and one StateFinalizationActivity class. SetState activities are used inside an EventHandlersActivity and StateInitializationActivity to move the state of the workflow.

When a StateActivity is executing, the only events that can be received are the events that can be handled by the EventDrivenActivity activities in the StateActivity and also the EventDrivenActivity activities attached to the enclosing StateActivity activities and the root Activity.

When the StateActivity starts running, the StateActivity will check to see whether a StateInitializationActivity activity is present or not. The StateActivity can have zero or one StateInitializationActivity activity. If a StateInitializationActivity activity is present the StateInitializationActivity will be executed. As soon as the StateInitializationActivity activity finishes, the StateActivity blocks events so that the StateActivity only receives events that can be handled by its EventDrivenActivity activities.

The StateActivity is a CompositeActivity, meaning the StateActivity activity can contain other activities.