Where are We?


In this chapter, we learned how WF program instances are executed in a durable and transactional manner. Because the execution progress of a WF program instance is recorded transactionally, it is possible to keep the state of the program consistent with the state of the external world, with which the program is interacting.

The transactionScopeActivity activity allows us to explicitly model transactional boundaries in a WF program. The transaction used by a transaction-ScopeActivity is the same transaction that is used to persist the WF program instance at the end of the execution of the transactionScopeActivity.

We saw how to write an activity that lets us declaratively specify persistence points in WF programs, and we were also reminded that a host application can initiate passivation (which entails persistence) at any time (except if a TRansactionScopeActivity is executing). Transactional services used by activities can participate in the transaction used for persistence, regardless of whether a transactionScopeActivity is employed in a WF program. And, external entities that enqueue items into WF program queues can also do work within the transaction that is used to persist the newly enqueued item as part of the WF program instance statein this way, we can achieve transaction handoff of data from external entities to WF program instances.




Essential Windows Workflow Foundation
Essential Windows Workflow Foundation
ISBN: 0321399838
EAN: 2147483647
Year: 2006
Pages: 97

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