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

Web Services


No product would be complete today if it did not send or receive SOAP envelopes over HTTP. WF includes a number of activities that revolve around web services, both as a client and a server.

The InvokeWebServiceActivity

The InvokeWebService activity can call an external web service. When we drop the activity into the workflow designer, the familiar Visual Studio Add Web Reference dialog box will appear. This same dialog appears when we add a web reference to any type of .NET project in Visual Studio. We merely need to browse to a Web Service Definition Language (WSDL) document with the description of the web service. Visual Studio will retrieve the WSDL and generate a proxy class for the web service. We can then configure the activity with the method name to invoke, and bind parameters to fields or properties in our workflow (see the screenshot).

The WebServiceActivity includes Invoking and Invoked event handlers that fire before and after the web service call, respectively...