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 Service Communication


Not all communications will be local communications. Windows Workflow provides web service interoperability as an additional feature. WF allows us to expose a workflow as a web service, and consume a web service from a workflow.

Workflows as Web Services

In this section, we'll build a workflow to deploy as a web service. Our starting project will be a sequential workflow library. A library is ideally suited for hosting in an ASP.NET web application. We can rename Workflow1.cs in the new project to HelloWorldWorkflow.

Just like local communication services, web services require a contract that defines the members of a web service. The contract is an interface, but without all the data exchange attributes we've used in previous communication interfaces. The interface for our HelloWorld workflow is shown below:

interface IHelloWorldService
{
string GetHelloWorldMessage(string name);
}

WebServiceInput Activity

The first activity for a web service workflow will be a WebServiceInput...