软件架构设计是现代软件开发的核心，它不仅是一门技术，更是一门艺术。然而，长期以来，还没有一本专门讲述.NET架构设计的书。

本书填补了这一缺憾。两位作者人选可谓众望所归，他们将GoF设计模式、Martin Fowler企业架构模式、Eric Evans领域驱动设计等业界精华与自己多年软件开发实战经验结合起来，深刻阐述了软件架构设计思想精髓。作者还从技术架构角度逐章讲述了业务层、服务层、数据访问层和表现层的分层设计，同时介绍了各种软件架构设计方案的优劣，如何在各种方案中做出抉择，以及如何将这些设计原则更具体地用到应用程序中。

书出自两位具有多年软件开发经验的 ASP .NET专家、作者和培训师之手，内容涉及多层架构、设计模式以及设计原则。第一部分简要介绍 UML、设计原则及模式；第二部分从技术架构角度讨论分层设计。本书行文流畅，语言通俗易懂，阐述了各种架构设计技术方案的优与劣，并讲述了如何在优与劣中做出权衡。中设计了真实的场景，展示了如何将这些设计原则更加具体地应用到 .NET应用程序中。

本书适合各层次 .NET开发人员阅读。

Part I　Principles

1　Architects and Architecture Today　3

　 What's a Software Architecture, Anyway?　4

　　　Applying Architectural Principles to Software　4

　　　What's Architecture and What's Not　8

　　　Architecture Is About Decisions　10

　　　Requirements and Quality of Software　12

　 Who's the Architect, Anyway?　17

　　　An Architect's Responsibilities　17

　　　How Many Types of Architects Do You Know?　20

　　　Common Misconceptions About Architects　21

　 Overview of the Software Development Process　24

　　　The Software Life Cycle　24

　　　Models for Software Development　26

　 Summary　30

　 Murphy's Laws of the Chapter　30

2　UML Essentials　31

　 UML at a Glance　32

　　　Motivation for and History of Modeling Languages　33

　　　UML Modes and Usage　36

　 UML Diagrams　41

　　　Use-Case Diagrams　43

　　　Class Diagrams　47

　　　Sequence Diagrams　53

　 Summary　61

　 Murphy's Laws of the Chapter　61

3　Design Principles and Patterns　63

　 Basic Design Principles　63

　　　For What the Alarm Bell Should Ring　65

　　　Structured Design　66

　　　Separation of Concerns　70

　 Object-Oriented Design　73

　　　Basic OOD Principles　73

　　　Advanced Principles　80

　 From Principles to Patterns　85

　　　What's a Pattern, Anyway?　86

　　　Patterns vs. Idioms　92

　　　Dependency Injection　95

　 Applying Requirements by Design　97

　　　Testability　97

　　　Security　108

　 From Objects to Aspects　116

　　　Aspect-Oriented Programming　11

　　　AOP in Action　120

　 Summary　124

　 Murphy's Laws of the Chapter　125

Part II　Design of the System

4　The Business Layer　129

　 What's the Business Logic Layer, Anyway?　130

　　　Dissecting the Business Layer　130

　　　Where Would You Fit the BLL?　134

　　　Business and Other Layers　138

　　　Patterns for Creating the Business Layer　141

　 The Transaction Script Pattern　145

　　　Generalities of the TS Pattern　145

　　　The Pattern in Action　149

　 The Table Module Pattern　154

　　　Generalities of the TM Pattern　155

　　　The TM Pattern in Action　159

　 The Active Record Pattern　165

　　　Generalities of the AR Pattern　166

　　　The AR Pattern in Action　168

　 The Domain Model Pattern　176

　　　Generalities of the DM Pattern　177

　　　The DM Pattern in Action　181

　 Summary　191

　 Murphy's Laws of the Chapter　192

5　The Service Layer　193

　 What's the Service Layer, Anyway?　194

　　　Responsibilities of the Service Layer　195

　　　What's a Service, Anyway?　198

　　　Services in the Service Layer　201

　 The Service Layer Pattern in Action　205

　　　Generalities of the Service Layer Pattern　205

　　　The Service Layer Pattern in Action　208

　 Related Patterns　213

　　　The Remote Fa?ade Pattern　213

　　　The Data Transfer Object Pattern　216

　　　The Adapter Pattern　218

　　　DTO vs. Assembly　221

　 Service-Oriented Architecture　229

　　　Tenets of SOA　230

　　　What SOA Is Not　232

　　　SOA and the Service Layer　234

　 The Very Special Case of Rich Web Front Ends　237

　　　Refactoring the Service Layer　238

　　　Designing an AJAX Service Layer　242

　　　Securing the AJAX Service Layer　246

　 Summary　250

　 Murphy's Laws of the Chapter　250

6　The Data Access Layer　251

　 What's the Data Access Layer, Anyway?　251

　　　Functional Requirements of the Data Access Layer　252

　　　Responsibilities of the Data Access Layer　254

　　　The Data Access Layer and Other Layers　260

　 Designing Your Own Data Access Layer　263

　　　The Contract of the DAL　263

　　　The Plugin Pattern　267

　　　The Inversion of Control Pattern　273

　　　Laying the Groundwork for a Data Context　277

　 Crafting Your Own Data Access Layer　280

　　　Implementing the Persistence Layer　281

　　　Implementing Query Services　289

　　　Implementing Transactional Semantics　298

　　　Implementing Uniquing and Identity Maps　305

　　　Implementing Concurrency　311

　　　Implementing Lazy Loading　315

　 Power to the DAL with an O/RM Tool　321

　　　Object/Relational Mappers　322

　　　Using an O/RM Tool to Build a DAL　325

　 To SP or Not to SP　333

　　　About Myths and Stored Procedures　333

　　　What About Dynamic SQL?　339

　 Summary　340

　 Murphy's Laws of the Chapter　341

7　The Presentation Layer　343

　 User Interface and Presentation Logic　344

　　　Responsibilities of the Presentation Layer　345

　　　Responsibilities of the User Interface　348

　　　Common Pitfalls of a Presentation Layer　350

　 Evolution of the Presentation Patterns　352

　　　The Model-View-Controller Pattern　353

　　　The Model-View-Presenter Pattern　364

　　　The Presentation Model Pattern　370

　　　Choosing a Pattern for the User Interface　372

　 Design of the Presentation　375

　　　What Data Is Displayed in the View?　375

　　　Processing User Actions　381

　 Idiomatic Presentation Design　390

　　　MVP in Web Presentations　390

　　　MVP in Windows Presentations　395

　 Summary　398

　 Murphy's Laws of the Chapter　399

Final Thoughts　401

Appendix: The Northwind Starter Kit　405

Index　413