Introduction
WF4 is one part of .NET Framework 4.0, which means WF4 workflow can be hosted and run in any type of application running with the .NET framework. We can host a workflow as a WCF service. We can also invoke a workflow service from a workflow or host workflow in an ASP.NET application and handle all the business logic behind the page.
When we design workflow applications, please let workflow be workflow. Don't couple workflow with other logic. For example, in this chapter, hosting workflow in ASP.NET is for conception demonstration only, not the best practice. In the real world, most of the time, workflow should be implemented as a workflow service hosted in IIS7 or AppFabric.
AppFabric is an IIS7 extension that includes many tools to help us host a workflow service. AppFabric is to workflow service like IIS7 is to ASP.NET website. However, we can run a workflow service in IIS7 without AppFabric installed. Although AppFabric is powerful, we need to spend some time to learn it....