Pro WF Windows Workflow in .NET 3.6

854 Pages·2008·17.68 MB·English

by  Bruce Bukovics

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Books for professionals By professionals® The eXperT’s Voice® in .neT
Companion eBook Available
Author of
Pro WF: Windows Workflow in .NET 3.5
Pro WF: Windows Workflow
P
in .NET 3.0
.NET 2.0 Interoperability Dear Reader,
Recipes: A Problem-Solution Since I began my career a few decades ago, I’ve looked for a better way to develop r Pro
Approach
software. I imagined that one day software would be developed visually instead
o
of with a text editor. I hoped that we would assemble complete applications
from prebuilt components, just as my son assembles his exorbitantly priced
plastic blocks.
W
Now the future is here with Microsoft’s Windows Workflow Foundation (WF).
WF
Why am I so excited about WF? Workflow-enabled applications use a declara-
tive programming model rather than a procedural one, separating what to do
from when to do it. And the WF designer is tightly integrated with Visual Studio,
bringing workflow within reach of every .NET developer. In the future, I believe
most nontrivial applications will be workflow-enabled, and WF is the de facto
standard workflow framework for Windows.
I wrote this book as a comprehensive tutorial on using WF. I start with the WF
fundamentals to get you up and running quickly. After that, I provide coverage F
of other WF topics, such as local services, event-driven activities, rules, work-
flow persistence, tracking, transactions, compensation, dynamic updates, web
services, ASP.NET, workflow markup, and hosting the workflow designers. I’ve
updated the first edition of this book with coverage of the new WF features in
.NET Framework 3.5, including a new chapter dedicated to workflow services.
I also added a new chapter that explores the development of composite and
WW
long-running custom activities.
As a working developer, I learn a new skill best through practical, hands-on
examples. So when I wrote this book, I focused on demonstrating WF concepts oi Windows Workflow in .NET 3.5
instead of just talking about them. I truly believe that workflows are the next par- n
adigm shift, and I hope this book helps you to use WF in your own applications. r
Thank you, kd
Bruce Bukovics fo
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Companion eBook o Use Windows Workflow Foundation to develop
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Bruce Bukovics
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Pro WF
Windows Workflow in .NET 3.5
■ ■ ■
Bruce Bukovics
Buckovics_975-1FRONT.fm Page ii Wednesday, May 28, 2008 4:59 PM
Pro WF: Windows Workflow in .NET 3.5
Copyright © 2008 by Bruce Bukovics
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For Teresa and Brennen
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Contents at a Glance
About the Author . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxi
About the Technical Reviewers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxiii
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xxv
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxvii
■ CHAPTER 1 A Quick Tour of Windows Workflow Foundation . . . . . . . . . . . . . . . . . 1
■ CHAPTER 2 Foundation Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
■ CHAPTER 3 Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
■ CHAPTER 4 Hosting the Workflow Runtime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
■ CHAPTER 5 Flow Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
■ CHAPTER 6 Local Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
■ CHAPTER 7 Event-Driven Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
■ CHAPTER 8 Workflow Persistence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297
■ CHAPTER 9 State Machine Workflows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333
■ CHAPTER 10 Transactions and Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369
■ CHAPTER 11 Workflow Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417
■ CHAPTER 12 Exception and Error Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 457
■ CHAPTER 13 Advanced Custom Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483
■ CHAPTER 14 Dynamic Workflow Updates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 519
■ CHAPTER 15 Workflow Tracking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 549
■ CHAPTER 16 Web Services and ASP.NET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 595
■ CHAPTER 17 Workflow Services and WCF Integration . . . . . . . . . . . . . . . . . . . . . . 625
■ CHAPTER 18 Workflow Serialization and Markup . . . . . . . . . . . . . . . . . . . . . . . . . . 693
■ CHAPTER 19 Hosting the Workflow Designers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 731
■ INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .793
v
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Contents
About the Author . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxi
About the Technical Reviewers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxiii
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xxv
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxvii
■ CHAPTER 1 A Quick Tour of Windows Workflow Foundation . . . . . . . . . . 1
Why Workflow? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Workflows Are Different. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Why Windows Workflow Foundation? . . . . . . . . . . . . . . . . . . . . . . . . . 2
Your Development Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Hello Workflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Creating the Workflow Project. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Introducing the Workflow Designer . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Using Workflow Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Entering Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Hosting the Workflow Runtime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Running the Application. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Passing Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Declaring the Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Passing Values at Runtime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Making Decisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Creating a Workflow Library . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Adding Workflow Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Adding IfElse Activities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Adding Calculation Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Creating the Calculator Client . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Testing and Debugging the Calculator. . . . . . . . . . . . . . . . . . . . . . . . 26
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
vii
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viii ■ CONTENTS
■ CHAPTER 2 Foundation Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Workflow Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Sequential Workflows. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
State Machine Workflows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Choosing a Workflow Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Foundation Deliverables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Class Libraries and Framework. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Runtime Engine. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Runtime Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Design-Time Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
.NET 2.0 Runtime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Runtime Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Application Host Process. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Runtime Engine. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Registered Core Services. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Registered Local Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Workflow Instance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Design-Time Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Workflow Authoring Modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Project Templates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Workflow Designer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Activity Designer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Rule Condition Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
RuleSet Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Workflow Debugger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Command-Line Workflow Compiler . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Command-Line Communication Activity Generator . . . . . . . . . . . . . 62
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
■ CHAPTER 3 Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Understanding Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
A Dual Audience for Activities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Class Hierarchy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Exploring Standard Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Custom Workflow Logic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Flow Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
State Management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Event Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Local Service Communication. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72