What does WF support us? "The Microsoft® .NET Framework 3.0 introduced
new capabilities for visually and declaratively building workflows that
can be hosted by managed code."
What are the types of workflow? According to WF, there are 2 types: sequential workflow & state machine workflow. However, what are the difference between them? This leads to another question:
What is "Sequential workflow" and What is "State machine workflow"? There is no definition from microsoft. - "In sequential workflows all decisions to
progress in the workflow are taken by the workflow itself. There’s a
well defined start and well defined end. Between there’s a flow
consisting of branches and loops to direct the flow. This means the
workflow is in control." (http://www.microsoft.com/belux/msdn/nl/community/columns/kurtclaeys/wf.mspx) - "With state machine workflows there’s no real predefined path of all
steps to undertake for a certain solution. State machines take another
approach. They wait for events to happen and based on these events they
change their state. State machines are used when the decisions are
coming in from an external application and are unpredictable. So
especially when there’s user interaction needed a state machine is a
more convenient solution. When new requirements come up, state machines are more
flexible to add features. Mostly it’s a matter of adding another state.
The state machine is not in control of the flow, but only controls the
set of choices which can be issued by another application." (http://www.microsoft.com/belux/msdn/nl/community/columns/kurtclaeys/wf.mspx)
There are several questions for us?
According to the above, the difference is that state machine workflows are care about extern events. The progress is driven by the events. Is it right? Second, what are proof to show that state machines are more flexible? Third, is sequential workflow just a special case of state machines workflow in which activities are states and edges between them are state transitions? Fourth, in implementation of workflow with Wf, what are the difference support of WF?
What is WF? "Windows Workflow Foundation is the programming model, engine and tools
for quickly building workflow enabledapplications on Windows."
"The State activity is a composite activity, meaning that it can contain
other activities. Once again there are restrictions to consider. A
state activity may contain only one StateInitialization activity, only
one StateFinalization activity, one or more EventDriven activities, and
one or more other State activities for nested states."
