CodeNotes for C# - Softcover

Softcover

ISBN 10: 0812966465 ISBN 13: 9780812966466

Publisher: Random House Trade Paperbacks, 2002

Synopsis

CodeNotes provides the most succinct, accurate, and speedy way for a developer to ramp up on a new technology or language. Unlike other programming books, CodeNotes drills down to the core aspects of a technology, focusing on the key elements needed in order to understand it quickly and implement it immediately. It is a unique resource for developers, filling the gap between comprehensive manuals and pocket references.

CodeNotes for C# illustrates Microsoft’s new language for the .NET platform, emphasizing syntax features and object-oriented concepts. Major capabilities of the .NET platform, including the Common Language Runtime (CLR), Base Class Libraries (BCL), and Assemblies, are also covered, as are popular .NET services such as ADO.NET, web services, and ASP.NET. This book is aimed at the experienced developer (Java, VB, C++, etc.) who wants to learn the C# language and evaluate its new features.
This edition of CodeNotes includes:

• A global overview of this technology and explanation of what problems it can be used to solve
• Real-world examples
• “How and Why” sections that provide hints, tricks, workarounds, and tips on what should be taken advantage of or avoided
• Instructions and classroom-style tutorials throughout from expert trainers and software developers

About this title

About the Author

Every CodeNotes title is written and reviewed by a team of commercial software developers and technology experts. See “About the Authors” at the front of the book for more information.

From the Inside Flap

ovides the most succinct, accurate, and speedy way for a developer to ramp up on a new technology or language. Unlike other programming books, CodeNotes drills down to the core aspects of a technology, focusing on the key elements needed in order to understand it quickly and implement it immediately. It is a unique resource for developers, filling the gap between comprehensive manuals and pocket references.

CodeNotes for C# illustrates Microsoft s new language for the .NET platform, emphasizing syntax features and object-oriented concepts. Major capabilities of the .NET platform, including the Common Language Runtime (CLR), Base Class Libraries (BCL), and Assemblies, are also covered, as are popular .NET services such as ADO.NET, web services, and ASP.NET. This book is aimed at the experienced developer (Java, VB, C++, etc.) who wants to learn the C# language and evaluate its new features.
This edition of CodeNotes includes:

A global overview of this t

Excerpt. © Reprinted by permission. All rights reserved.

Chapter 1

INTRODUCTION

Innovation is the hallmark of the software industry. Like clockwork, the widespread adoption of a particular standard is frequently accompanied by the introduction of a new one. Programming languages are no exception. Drawing upon both theory and practice, a new language will often address the shortcomings and limitations of its predecessors while boasting innovations to boot. So it is with C#.

As you have likely heard, C# (pronounced "C-Sharp") is a new programming language designed by Microsoft. Although the spectrum of existing documentation on C# can give varying impressions as to its place within the software development community, a diagnosis of the language is prone to the following two distinct observations:

1. Formally, C# is a specification for a computer language that Microsoft announced in June 2000. Syntactically, the language is similar to C++ and Java, eliminating (or obscuring) many of the complexities of the former while improving on some of the conventions of the latter. The C# specification was recently ratified by the European Computer Manufacturers Association (ECMA), which means that other vendors can provide their own implementations of the language. Therefore, writing C# applications for operating systems other than Windows will be possible (in fact, as we will see, it is already possible).

2. Practically, C# is the "native" language of the .NET Framework, which is Microsoft's new strategy for the development and deployment of software. As we will see throughout this book, in addition to revamping significant portions of Windows architecture, .NET improves upon existing Microsoft technologies such as ActiveX Data Objects (ADO, for database access) and Active Server Pages (ASP, for web development). Furthermore, .NET introduces some fundamentally new concepts into the realm of software development, such as cross-language inheritance and component versioning through public-key cryptography.

 In this regard, C# is not so much a new creature as an improved form of older languages that has been adapted to the .NET environment. For developers C# can serve as an excellent entry point into the .NET world (although, as we will see, other languages are also supported by the framework). By using C# to leverage the .NET Framework you can develop a variety of applications, including traditional Windows desktop applications, web-based applications, and software components that communicate over the open standards of the Internet (web services).

In this book we will examine both the theory and practice behind C#. Whereas theory encompasses the syntactical conventions of the language (such as supported variable types, loop constructs, and object-oriented features), practice incorporates the surrounding .NET Framework on which a C# application executes. Remember, however, that technically C# is nothing more than language specification, and while in practice it is intrinsically tied to .NET, there is no stipulation that it remain so. (An open source effort to port the language to Linux is already in progress; see aCS010001 for details.) Nevertheless, a portion of this book is dedicated to exploring the natural habitat of C#, which is .NET.

C# Is Just Another Language . . .

While it is easy to become buried in the marketing hyperbole, remember that C# is just another language. Although there are some noteworthy innovations with Microsoft's latest creature, the language merely builds on concepts with which you are likely familiar. Memory allocation, array usage, and class inheritance are all-important aspects of C#, though they may be used with slightly different conventions and assumptions than the language you are currently using.

What is special about C# is that it was designed specifically with component development in mind. This means that authoring classes in C# is extremely straightforward because of the language's intrinsic support for component-based features such as properties and events (in contrast to existing languages that obscure the process to varying degrees).

From a syntax perspective, C# is a derivative of the "C" language family, which means that C++ and Java developers will be able to pick it up with relative ease. The language will pose more of a challenge to Visual Basic developers because its syntax is not as rich or "English-like." In addition, C# is built on object-oriented (OO) features such as inheritance, polymorphism, and interfaces, which were either absent or obscured in Visual Basic 6. In the upcoming orientation section we will expand on some of the challenges that developers will face as they migrate from a particular language to C#.

. . . and a Completely New Framework

C# may be just another language, but it is built on a fundamentally new framework. It can be argued that .NET represents the most significant architectural change in Microsoft technology since the introduction of 32-bit Windows 95. Many of the concepts and technologies that you may be familiar with, such as DLLs, COM, and ActiveX, have been overhauled or deprecated by .NET. (As we will see, however, they have not been rendered obsolete because there is still a place for legacy technologies within the framework.) In addition, .NET applications are not run directly by the operating system but instead execute through an intermediary called the Common Language Runtime (CLR), which in some ways is similar to a Java Virtual Machine (VM).

Two Steps

Given these two aspects of Microsoft's new development tool, the requirements for becoming a productive C# developer are twofold:

1. You must familiarize yourself with the conventions of the language. This includes understanding how C# syntax elements (classes, functions, loops, etc.) are utilized as well as learning how programmatic tasks (such as the manipulation of strings) are carried out.

2. You must understand the intricacies of the .NET Framework. To this end let us now examine exactly what the .NET Framework is.

THE .NET FRAMEWORK

C# is simply a piece of a larger and more encompassing entity: Microsoft's new .NET Framework. Depending on your interests and development background, you may already have a number of ideas as to what the .NET Framework entails. As we will see in this book:

* .NET fundamentally changes the manner in which applications execute under the Windows Operating System. With .NET, Microsoft is in effect abandoning its traditional stance, which favors compiled components, and is embracing Virtual Machine (VM) technology (similar in many ways to the Java paradigm).

* In addition to introducing C#, .NET brings about significant changes to both Visual Basic and Visual C++. .NET also provides a common library for all languages (discussed shortly).

* .NET is built from the ground up with the Internet in mind and embraces open Internet standards such as XML and HTTP. XML is also used throughout the framework as a messaging instrument, for file storage configuration, and for documentation purposes in C#.

These are all noteworthy features of the .NET Framework, which consists of the platform and tools needed to develop and deploy .NET applications. We will take a closer look at the .NET Framework in Chapter 3, but its essential components are summarized here. For a thorough introduction, however, please see CodeNotes for .NET.

The Common Language Runtime

The Common Language Runtime (CLR) is the execution engine for all programs in the .NET Framework. The CLR is similar to a Java Virtual Machine (VM) in that it executes byte code on the fly while simultaneously providing services such as garbage collection and exception handling. Unlike a Java VM, which is limited to the Java language, the CLR is accessible from any compiler that produces Microsoft Intermediate Language (IL) code, which is similar to Java byte code. Code that executes within the CLR is referred to as "managed" code. Code that executes outside its boundaries (such as VB6 and Win32 applications) is called "unmanaged" code. The C# compiler does not translate source code into native machine code but converts it into IL code, which is, in turn, run by the CLR. Therefore, C# applications are said to be "managed" by the CLR.

The Base Class Libraries

In C# (and in .NET), functionality is exposed through a collection of classes called the Base Class Libraries (BCL). The BCL provides thousands of prewritten classes that you can leverage for services such as File I/O, database access, and common operations such as sorting. Consider, for example, how you currently manipulate a string. The approach depends, of course, on the language you use:

* Visual Basic users would leverage built-in language functions such as Mid$(), InStr$(), etc.

* C++ developers could manipulate the string directly in memory (using pointers) or, more likely, leverage prewritten libraries such as the C-Runtime Library, the Standard Template Library (STL), or the Microsoft Foundation Classes (MFC).

* Those using Java would utilize the String or StringBuffer class of the Java Class Libraries (JCL). (Java users will find the BCL very similar to the JCL.)

In C# you manipulate strings by using the System.String and System.StringBuilder classes found in the BCL. The BCL is significant because it is accessible to any language that targets the CLR (not just C#). This is in contrast to pre-.NET technology where every language has its own supporting libraries that are accessible only from that particular language (the MFC, for example, is only accessible from C++). Thus, once you understand how to use the System.String class, you can leverage it not only from C# but from any of the .NET languages discussed below.

C# Compiler Tools

Writing .NET applications requires a compiler that translates source code into IL code. There are two ways to perform the compilation process in...

Edition details

• Publisher: Random House Trade Paperbacks
• Publication date: 2002
• Language: English
• ISBN 10: 0812966465
• ISBN 13: 9780812966466
• Binding: Paperback
• Number of pages: 272
• Editor: Brill Gregory