Professional Visual Basic® 2010 and .NET 4

Chapter 26. Windows Workflow Foundation

WHAT YOU WILL LEARN IN THIS CHAPTER

• What is workflow?

• How Windows Workflow Foundation abstracts workflow in your applications

• How you build workflows with Windows Workflow Foundation

• How you can extend Windows Workflow Foundation by creating custom activities

• How you can integrate Windows Workflow Foundation into your applications

Windows Workflow Foundation (WF) is a powerful tool when developing applications, as it provides a standard means of adding workflow to an application. Workflow refers to the steps involved in an application. Most business applications contain one or more workflows, such as the approval steps in an expense-tracking application or the steps involved in paying for a cart full of items at an online store. Normally, a workflow is created in code and is an integral part of the application. WF enables developers to graphically build the workflow, keeping it logically separated from the code itself. It also enables the workflow to change as the needs of the business change. These workflows may be as complex as needed and may integrate child workflows, human processes, or Web services.

This chapter looks at how you can take advantage of WF in your applications: how you can add and edit workflows, how you can integrate workflows into an existing business process, and how the graphical tools used to build workflows with Visual Studio can help you communicate with business users and avoid errors caused by mistakes in the workflow. ...