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.
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.
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.
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 the book. However, this chapter is suitable for reading at any time, perhaps most appropriately immediately following Chapter 1.
Here is a description of each chapter.
- Chapter 1—Introducing C#: After presenting the C#
HelloWorld program, this chapter proceeds to dissect it. This should familiarize readers with the look and feel of a C# program and provide details on how to compile and debug their own programs. It also touches on the context of a C# program’s execution and its intermediate language.
- Chapter 2—Data Types: Functioning programs manipulate data, and this chapter introduces the primitive data types of C#. This includes coverage of two type categories, value types and reference types, along with conversion between types and support for arrays.
- Chapter 3—Operators and Control Flow: To take advantage of the iterative capabilities in a computer, you need to know how to include loops and conditional logic within your program. This chapter also covers the C# operators, data conversion, and preprocessor directives.
- Chapter 4—Methods and Parameters: This chapter investigates the details of methods and their parameters. It includes passing by value, passing by reference, and returning data via a parameter. In C#, default parameters are not supported, and this chapter explains why and how to provide the same functionality.
- Chapter 5—Classes: Given the basic building blocks of a class, this chapter combines these constructs together to form fully functional types. Classes form the core of object-oriented technology by defining the template for an object.
- Chapter 6—Inheritance: Although inheritance is a programming fundamental to many developers, C# provides some unique constructs, such as the new modifier. This chapter discusses the details of the inheritance syntax, including overriding.
- Chapter 7—Interfaces: This chapter demonstrates how interfaces are used to define the “versionable” interaction contract between classes. C# includes both explicit and implicit interface member implementation, enabling an additional encapsulation level not supported by most other languages.
- Chapter 8—Value Types: Although not as prevalent as defining reference types, it is sometimes necessary to define value types that behave in a fashion similar to the primitive types built into C#. This chapter describes how to define structures, while exposing the idiosyncrasies they may introduce.
- Chapter 9—Well-Formed Types: This chapter discusses more advanced type definition. It explains how to implement operators, such as + and cast, and describes how to encapsulate multiple classes into a single library. In addition, the chapter demonstrates defining namespaces and XML comments, and discusses how to design classes for garbage collection.
- Chapter 10—Exception Handling: This chapter expands on the exception-handling introduction from Chapter 4 and describes how exceptions follow a hierarchy that enables creating custom exceptions. It also includes some best practices on exception handling.
- Chapter 11—Generics: Generics is perhaps the core feature missing from C# 1.0. This chapter fully covers this new feature.
- Chapter 12—Collections: Given generics, all the collection classes in .NET 1.1 can be replaced with their generic equivalents. This chapter reviews the collection classes, along with the interfaces that define their common behavior. With minimal impact on the underlying runtime, C# 2.0 provides syntax for easier collection creation with iterators. Iterators provide a clean syntax for specifying how to loop through data within a class.
- Chapter 13—Delegates and Events: Delegates begin clearly distinguishing C# from its predecessors by defining patterns for handling events within code. This virtually eliminates the need for writing routines that poll. Encapsulated delegates, known as events, are a core construct of the Common Language Runtime. Anonymous methods, another C# 2.0 feature, are also presented here.
- Chapter 14—Reflection and Attributes: Object-oriented programming formed the basis for a paradigm shift in program structure in the late 1980s. In a similar way, attributes facilitate declarative programming and embedded metadata, ushering in a new paradigm. This chapter looks at attributes and discusses how to retrieve them via reflection. It also covers file input and output via the serialization framework within the Base Class Library.
- Chapter 15—Multithreading: Most modern programs require the use of threads to execute long-running tasks while ensuring active response to simultaneous events. As programs become more sophisticated, they must take additional precautions to protect data in these advanced environments. Programming multithreaded applications is complex. This chapter discusses how to work with threads and provides best practices to avoid the problems that plague multithreaded applications.
- Chapter 16—Multithreading Patterns: Building on the last chapter, this one demonstrates some of the built-in threading pattern support that can simplify the explicit control of multithreaded code.
- Chapter 17—Platform Interoperability and Unsafe Code: Given that C# is a relatively young language, far more code is written in other languages than in C#. To take advantage of this preexisting code, C# supports interoperability—the calling of unmanaged code—through P/Invoke. In addition, C# provides for the use of pointers and direct memory manipulation. Although code with pointers requires special privileges to run, it provides the power to interoperate fully with traditional C-based application programming interfaces.
- Chapter 18—The Common Language Infrastructure: Fundamentally, C# is the syntax that was designed as the most effective programming language on top of the underlying Common Language Infrastructure. This chapter delves into how C# programs relate to the underlying runtime and its specifications.
- Appendix A—Downloading and Installing the C# Compiler and the CLI Platform: This appendix provides instructions for setting up a C# compiler and the platform on which to run the code, Microsoft .NET or Mono.
- Appendix B—Complete Source Code Listings: In several cases, a full source code listing within a chapter would have been too long. To make these listings still available to the reader, this appendix includes the full listing from Chapters 3, 11, 12, 14, and 17.
- Appendix C—C# 2.0 Topics: This appendix provides a quick reference to any C# 2.0 content. It is specifically designed to help C# 1.0 programmers quickly get up to speed on the 2.0 features.
I hope you find this book to be a great resource in establishing your C# expertise and that you continue to reference it for the more obscure areas of C# and its inner workings.