Professional C# 5.0 and .NET 4.5.1

Chapter 45Windows Workflow Foundation

WHAT’S IN THIS CHAPTER?

• Learning the different types of workflows that you can create
• Exploring descriptions of some of the built-in activities
• Creating custom activities
• Getting an overview of a workflow

WROX.COM CODE DOWNLOADS FOR THIS CHAPTER

The wrox.com code downloads for this chapter are found at www.wrox.com/go/procsharp on the Download Code tab. The code for this chapter is divided into the following major examples:

• Hello World
• Parallel Execution
• Pick Demo
• Custom Activities
• Args and Vars
• Workflow Application
• Workflow as Services
• Dynamic Update
• Designer Hosting

A WORKFLOW OVERVIEW

This chapter presents an overview of the Windows Workflow Foundation 4.5 (referred to as WF and Workflow throughout the rest of this chapter), which provides a model to define and execute processes using a set of building blocks called activities. WF provides a Designer that, by default, is hosted within Visual Studio, which enables you to drag and drop activities from the toolbox onto the design surface to create a workflow template.

This template can then be executed in a number of different ways, as explained throughout the chapter. As a workflow executes, it may need to access the outside world, and there are a couple of methods typically used that enable you to do this. In addition, a workflow may need to save and restore its state, for example, when a long wait is needed.

A workflow is constructed from a number of activities, and these activities ...