Throughout the history of software engineering, the methodology used to write computer programs has undergone several paradigm shifts, each building on the foundation of the former by increasing code organization and decreasing complexity. This book takes you through these same paradigm shifts. The beginning chapters take you through sequential programming structure in which statements are written in the order in which they are executed. The problem with this model is that complexity increases exponentially as the requirements increase. To reduce this complexity, code blocks are moved into methods, which creates a structured programming model . This allows you to call the same code block from multiple locations within a program, without duplicating code. Even with this construct, however, programs quickly become unwieldy and require further abstraction. From this emerges object-oriented programming, which Chapter 5 discusses.

In subsequent chapters, you continue to learn about additional methodologies, such as interface-based programming, and eventually rudimentary forms of declarative programming (in Chapter 14) via attributes. This book has three main functions. It provides comprehensive coverage of the C# language, going beyond a tutorial and offering a foundation upon which you can begin effective software development projects. For readers already familiar with C#, this book provides insight into some of the more complex programming paradigms and provides in-depth coverage of the features introduced in the latest version of the language, C# 2.0. It serves as a timeless reference, even after you gain proficiency with the language. The key to successfully learning C# is to start coding as soon as possible. Don''t wait until you are an "expert" in theory; start writing software immediately.

As a believer in iterative development, I hope this book enables even a novice programmer to begin writing basic C# code by the end of Chapter 2. A number of topics are not covered in this book. You won''t find coverage of topics such as ASP.NET, ADO.NET, smart client development, distributed programming, and so on. Although these topics are relevant to the .NET framework, to do them justice requires books of their own. Fortunately, Addison-Wesley''s Microsoft .

NET Development Series provides a wealth of writing on these topics. Reading this book will prepare you to focus on and develop expertise in any of these areas. It focuses on C# and the types within the Base Class Library. Target Audience for This Book My challenge with this book was how to keep advanced developers awake while not abandoning beginners by using words like "assembly," "link," "chain," "thread," and "fusion," as if the topic was more appropriate for blacksmiths than for programmers. This book''s primary audience is experienced developers looking to add another language to their quiver. However, I have carefully assembled this book to provide significant value to developers at all levels. Beginners: If you are new to programming, this book serves as a resource to help transition you from an entry-level programmer to a C# developer, comfortable with any C# programming task that''s thrown your way. This book not only teaches you syntax, but it also trains you in good programming practices that will serve you throughout your programming career.

Structured programmers: Just as it''s best to learn a foreign language through immersion, learning a computer language is most effective when you begin using it before you know all the intricacies. In this vein, the book begins with a tutorial that will be comfortable for those familiar with structured programming, and by the end of Chapter 4, developers in this category should feel at home writing basic control flow programs. However, the key to excellence for C# developers is not memorizing syntax. To transition from simple programs to enterprise development, the C# developer must think natively in terms of objects and their relationships. To this end, Chapter 5''s Beginner Topics introduce classes and object-oriented development. The role of historically structured programming languages such as C, COBOL, and FORTRAN is still significant but shrinking, so it behooves software engineers to become familiar with object-oriented development. C# is an ideal language for making this transition because it was designed with object-oriented development as one of its core tenets. Object-based and object-oriented developers: C++ and Java programmers, and many experienced Visual Basic programmers, fall into this category.

Many of you are already completely comfortable with semicolons and curly braces. A brief glance at the code in Chapter 1 reveals that at its core, C# is similar to the C and C++ style languages that you already know. C# professionals: For those already versed in C#, this book provides a convenient reference for less frequently encountered syntax. Furthermore, it provides answers to language details and subtleties seldom addressed. Most importantly, it presents the guidelines and patterns for programming robust and maintainable code. This book also aids in the task of teaching C# to others. With the emergence of C# 2.0, some of the most prominent enhancements are: Partial classes (see Chapter 5) Global namespace qualifiers (see Chapter 9) Different access modifiers on property getters and setters (see Chapter 5) Anonymous methods (see Chapter 13) Generics (see Chapter 11) Iterator topics (see Chapter 12) These topics are covered in detail for those not already familiar with them.

Also pertinent to advanced C# development is the subject of pointers, in Chapter 17. Even experienced C# developers often do not understand this topic well. Features of This Book Essential C# 2.0 is a language book that adheres to the core C# Language 2.0 Specification. To help you understand the various C# constructs, it provides numerous examples demonstrating each feature. Accompanying each concept are guidelines and best practices, ensuring that code compiles, avoids likely pitfalls, and achieves maximum maintainability. To improve readability, code is specially formatted and chapters are outlined using mind maps.

Code Samples The code snippets in most of this text can run on any implementation of the Common Language Infrastructure (CLI), including the Mono, Rotor, and Microsoft .NET platforms. Platform- or vendor-specific libraries are seldom used, except when communicating important concepts relevant only to those platforms (appropriately handling the single-threaded user interface of Windows, for example). Any code that specifically requires C# 2.0 compliance is called out in Appendix C: C# 2.0 Topics. Although it might have been convenient to provide full code samples that you could copy into your own programs, doing so would detract you from learning a particular topic. Therefore, you need to modify the code samples before you can incorporate them into your programs.

The core omission is error checking, such as exception handling. Also, code samples do not explicitly include using System statements. You need to assume the statement throughout all samples. You can find sample code at http://mark.michaelis.net and at www.awprofessional.com/title/0321150775.

Mind Maps Each chapter''s introduction includes a mind map , which serves as an outline that provides at-a-glance reference to each chapter''s content. The theme of each chapter appears in the mind map''s center. High-level topics spread out from the core. Mind maps allow you to absorb the flow from high-level to more detailed concepts easily, with less chance of encountering very specific knowledge that you might not be looking for. Helpful Notes Depending on your level of experience, special code blocks and notes will help you navigate through the text. Beginner Topics provide definitions or explanations targeted specifically toward entry-level programmers. Advanced Topics enable experienced developers to focus on the material that is most relevant to them. Callout notes highlight key principles in callout boxes so that readers easily recognize their significance.

Language Contrast sidebars identify key differences between C# and its predecessors to aid those familiar with other languages. How This Book Is Organized At a high level, software engineering is about managing complexity, and it is toward this end that I have organized Essential C# 2.0 . Chapters 1-4 introduce structured programming, which enable you to start writing simple functioning code immediately. Chapters 5-9 present the object-oriented constructs of C#. Novice readers should focus on fully understanding this section before they proceed to the more advanced topics found in the remainder of this book. Chapters 11-13 introduce additional complexity-reducing constructs, handling common patterns needed by virtually all modern programs. This leads to dynamic programming with reflection and attributes, which is used extensively for threading and interoperability, the chapters that follow.

The book ends with a chapter on the Common Language Infrastructure, which describes C# within the context of the development platform in which it operates. This chapter appears at the end because it is not C# specific and it departs from the syntax and programming style in the rest of.