Book Image

Programming Windows Workflow Foundation: Practical WF Techniques and Examples using XAML and C#

By : Kenneth Scott Allen
Book Image

Programming Windows Workflow Foundation: Practical WF Techniques and Examples using XAML and C#

By: Kenneth Scott Allen

Overview of this book

Windows Workflow Foundation (WF) is a technology for defining, executing, and managing workflows. It is part of the .NET Framework 3.0 and will be available natively in the Windows Vista operating system. Windows Workflow Foundation might be the most significant piece of middleware to arrive on the Windows platform since COM+ and the Distributed Transaction Coordinator. The difference is, not every application needs a distributed transaction, but nearly every application does have a workflow encoded inside it. In this book, K Scott Allen, author of renowned .NET articles at www.odetocode.com, provides you with all the information needed to develop successful products with Windows Workflow. From the basics of how Windows Workflow can solve the difficult problems inherent in workflow solutions, through authoring workflows in code, learning about the base activity library in Windows Workflow and the different types of workflow provided, and on to building event-driven workflows using state machines, workflow communications, and finally rules and conditions in Windows Workflow, this book will give you the in-depth information you need. Throughout the book, an example "bug reporting" workflow system is developed, showcasing the technology and techniques used.
Table of Contents (14 chapters)
Programming Windows Workflow Foundation: Practical WF Techniques and Examples using XAML and C#
Credits
About the Author
About the Reviewer
Preface

Chapter 6. Workflow Hosting

Windows Workflow is a runtime and not an application. A host process must load and launch the workflow runtime before starting a workflow. The host process tells the runtime the types of workflows to create, and the runtime manages the life cycle of the workflows and notifies the host process about important life cycle events, such as workflow completion and termination. The runtime isn't particular about the type of host it lives inside. The host process could be a smart client application running on an office desktop machine, or an ASP.NET worker process running on a server in the rack of a data center. All the host processes needs is the ability to load the .NET 3.0 Workflow assemblies.

A host can also customize the workflow runtime by layering additional services on top of the runtime's base feature set. These services can provide persistence support for long-running workflows, tracking support for monitoring workflow execution, and more. Recall the ExternalDataExchangeService...