I got a review copy of K. Scott Allen's "Programming Windows Workflow Foundation: Practical WF Techniques and Examples using XAML and C#" book and I just finished reading it recently, and wanted to take a moment to mention my opinion about it.

First of all, I'm probably not quite Scott's target audience, seeing how I was already familiar with WF before getting into the book. From my point of view, the book aims to provide a quick introduction to what WF is and how to get started programming it. In that aspect, I think it does a pretty good job.

The book starts by quickly introducing what WF and what it is composed of (the runtime, activities, designer, XAML and so on). Chapter 2 then talks in a bit more detail about how to create and design workflows, covering both the principal aspects of how the VS designer works, as well as writing workflows in code and XAML. But this chapter also goes a bit further and covers using the workflow compiler both from the command line (wfc.exe) as well as programmatically and XAML workflow activation.

Chapter 3 is dedicated to writing sequential workflows, though it also covers basic host <-> workflow communication using the workflow runtime events, workflow parameters and external data services. The latter are taken up in more detail in chapter 4, which covers most of the basic activities in the base activity library.

Chapter 5 introduces how to write custom activities. While the cover here is somewhat light (as expected given the breath of the topic), Scott does quickly cover important topics like activity binding and dependency properties and gives a quick look to readers of how to write custom activity designers and validators. Chapter 6 covers the hosting facilities in WF, including how to correctly use the WorkflowRuntime class, and all the built-in runtime services, including scheduling, persistence and tracking.

Chapter 7 covers State-Machine workflows, including some simple examples of how to interact with the workflow from the host (like quering possible transitions from the current state). Chapter 8 covers host <-> workflow communication in detail, including the use of correlation tokens, role authorization and an explanation of workflow queues. Finally, Chapter 9 covers the rules engine in WF and using code and rule conditions in activities.

As I said earlier, I'm probably not the the target reader for the book. Many of my readers probably won't also, so if you're looking for a comprehensive, in depth look at WF, you'll want to find some other source.

However, if you are not familiar with WF yet, I believe Scott's book is a pretty good place to start. Here's why:

• The book is short, about 230 pages. Most people should be able to go through the book pretty quickly.
• Scott's writing is very much to my liking. He's direct, goes straight to the point without any B.S. and he's style is pretty engaging overall, so you won't get easily bored. Chapters are also very reasonably paced and good in length, so you can very easily read it chapter-at-a-time (I hate books with never-ending chapters!).
• Even though the book is short, Scott still manages to cram a lot of useful information and cover a lot of topics (some in much more detail than I honestly expected) and I think its fair to say he does a good job of putting all the options and facilities in WF in front of his readers.

While on the topic of introducing WF, my good friend Sam Gentile wrote a couple of days an introductory post on WF which is pretty good. Like others, I'm also looking forward to seeing Sam share a bit more of his findings and what he has learned about the platform just as he has in the past with WCF and other technologies.

Look for my take on Dharma Shukla's and Bob Schmidt's "Essential Windows Workflow Foundation" book in a post near you!

Windows Workflow Foundation, WF, Book Reviews