About the Author
Dr. Harvey Deitel is one of the world's leading computer science instructors and seminar presenters, and author of more than a dozen books. He worked on the pioneering operating system teams in industry and academia that developed many of the techniques at the heart of operating systems like UNIX®, Windows NT™ and OS/2™.Paul Deitel
has taught Visual Basic, Java, C and C++ at numerous hardware and software companies, including Sun Microsystems, Digital Equipment Corporation, IBM, Open Environment Corporation, Adra Systems, and Cambridge Technology Partners, and is himself an expert developer.
The Deitels are principals of Deitel & Associates, Inc., an international training organization specializing in Visual Basic, Java, C and C++, and object technologies.
Excerpt. © Reprinted by permission. All rights reserved.
Live in fragments no longer. Only connect.
Edward Morgan Forster
We wove a web in childhood,
A web of sunny air.
Welcome to Visual Basic .NET and the exciting world of Windows, Internet and World-Wide-Web programming with Visual Studio and the .NET platform! This book is the first in our new .NET How to Program series, which presents various leading-edge computing technologies in the context of the .NET platform.
Visual Basic .NET provides the features that are most important to programmers, such as object-oriented programming, strings, graphics, graphical-user-interface (GUI) components, exception handling, multithreading, multimedia (audio, images, animation and video), file processing, prepackaged data structures, database processing, Internet and World-Wide-Web-based client/server networking and distributed computing. The language is appropriate for implementing Internet-based and World-Wide-Web-based applications that seamlessly integrate with PC-based applications. Visual Basic .NET is the next phase in the evolution of Visual Basic, the world's most popular programming language.
The .NET platform offers powerful capabilities for software development and deployment, including independence from a specific language or platform. Rather than requiring developers to learn a new programming language, programmers can contribute to the same software project, but write code using any (or several) of the .NET languages (such as Visual Basic .NET, Visual C++ .NET, C# and others) with which they are most competent. In addition to providing language independence, .NET extends program portability by enabling .NET applications to reside on, and communicate across, multiple platforms—thus facilitating the delivery of Web services over the Internet. .NET enables Web-based applications to be distributed to consumer-electronic devices, such as cell phones and personal digital assistants, as well as to desktop computers. The capabilities that Microsoft has incorporated into the .NET platform create a new software-development paradigm that will increase programmer productivity and decrease development time.
New Features in Visual Basic.NET How to Program: Second Edition
This edition contains many new features and enhancements, including:
- Full-Color Presentation. This book is now in full color. In the book's previous edition, the programs were displayed in black and the screen captures appeared in a second color. Full color enables readers to see sample outputs as they would appear on a color monitor. Also, we now syntax color the Visual Basic .NET code, similar to the way Visual Studio .NET colors the code in its editor window. Our syntax-coloring conventions are as follows:
- comments appear in green
- keywords appear in dark blue
- literal values appear in light blue
- text, class, method and variable names appear in black
- errors and ASP delimiters appear in red
- "Code Washing." This is our term for the process we use to format the programs in the book so that they have a carefully commented, open layout. The code appears in full color and grouped into small, well-documented pieces. This greatly improves code readability—an especially important goal for us, considering that this book contains about 21,000 lines of code.
- Web Services and ASP.NET. Microsoft's .NET strategy embraces the Internet and Web as integral to the software development and deployment processes. Web services, a key technology in this strategy, enables information sharing, commerce and other interactions using standard Internet protocols and technologies, such as Hypertext Transfer Protocol (HTTP), Simple Object Access Protocol (SOAP) and Extensible Markup Language (XML). Web services enable programmers to package application functionality in a form that turns the Web into a library of reusable software components. In Chapter 21, ASP .NET and Web Services, we present a Web service that allows users to make airline seat reservations. In this example, a user accesses a Web page, chooses a seating option and submits the page to the Web server. The page then calls a Web service that checks seat availability. We also present information relating to Web services in Appendix N, Crystal Reports for Visual Studio .NET, which discusses popular reporting software for database-intensive Visual Basic .NET applications. Crystal Reports, which is integrated into Visual Studio .NET, provides the ability to expose a report as a Web service. The appendix provides introductory information and then directs readers to a walkthrough of this process on the Crystal Decisions Web site (www.crystaldecisions.com/net).
- Web Forms, Web Controls and ASP.NET. Applications developers must be able to create robust, scalable Web-based applications. The .NET platform architecture supports such applications. Microsoft's .NET server-side technology, Active Server Pages (ASP) .NET, allows programmers to build Web documents that respond to client requests. To enable interactive Web pages, server-side programs process information users input into HTML forms. ASP .NET is a significant departure from previous versions of ASP, allowing developers to program Web-based applications using the powerful object-oriented languages of .NET. ASP .NET also provides enhanced visual programming capabilities, similar to those used in building Windows forms for desktop programs. Programmers can create Web pages visually, by dragging and dropping Web controls onto a Web form. Chapter 20, ASP .NET, Web Forms and Web Controls, introduces these powerful technologies.
- Object-Oriented Programming. Object-oriented programming is the most widely employed technique for developing robust, reusable software, and Visual Basic .NET offers enhanced object-oriented programming features. This text offers a rich presentation of object-oriented programming. Chapter 8, Object-Based Programming, introduces how to create classes and objects. These concepts are extended in Chapter 9, Object-Oriented Programming: Inheritance—which discusses how programmers can create new classes that "absorb" the capabilities of existing classes. Chapter 10, Object-Oriented Programming: Polymorphism—familiarizes the reader with the crucial concepts of polymorphism, abstract classes, concrete classes and interfaces, which facilitate powerful manipulations among objects belonging to an inheritance hierarchy.
- XML. Use of Extensible Markup Language (XML) is exploding in the software-development industry, the e-business and e-commerce communities, and is pervasive throughout the.NET platform. Because XML is a platform-independent technology for describing data and for creating markup languages, XML's data portability integrates well with Visual Basic .NET's portable applications and services. Chapter 18, Extensible Markup Language (XML) introduces XML. In this chapter, we introduce basic XML markup and discuss the technologies such as DTDs and Schema, which are used to validate XML documents' contents. We also explain how to programmatically manipulate XML documents using the Document Object Model (DOM™) and how to transform XML documents into other types of documents via Extensible Stylesheet Language Transformations (XSLT).
- Multithreading. Computers enable us to perform many tasks in parallel (or concurrently), such as printing documents, downloading files from a network and surfing the Web. Multithreading is the technology through which programmers can develop applications that perform concurrent tasks. Historically, a computer has contained a single, expensive processor, which its operating system would share among all applications. Today, processors are becoming so inexpensive that it is possible to build affordable computers containing many processors that work in parallel—such computers are called multiprocessors. Multithreading is effective on both single-processor and multiprocessor systems. Visual Basic .NET's multithreading capabilities make the platform and its related technologies better prepared to deal with today's sophisticated multimedia-intensive, database-intensive, network-based, multiprocessor-based, distributed applications. Chapter 14, Multithreading provides a detailed discussion of multithreading.
- Visual Studio .NET Debugger. Debuggers are programs that help programmers find and correct logic errors in program code. Visual Studio .NET contains a powerful debugging tool that allows programmers to analyze their program line-byline as the program executes. In Appendix D, Visual Studio .NET Debugger, we explain how to use key debugger features, such as setting breakpoints and "watches," stepping into and out of procedures, and examining the procedure call stack.
- Appendix C, Career Opportunities. This appendix introduces career services available on the Internet. We explore online career services from both the employer's and employee's perspectives. We list many Web sites at which you can submit applications, search for jobs and review applicants (if you are interested in hiring someone). We also review services that build recruiting pages directly into e-businesses. One of our reviewers told us that he had used the Internet as a primary tool in a recent job search, and that this appendix would have helped him expand his search dramatically.
- Appendix F, Unicode. As computer systems evolved worldwide, computer vendors developed numeric representations of character sets and special symbols for the local languages spoken in different countries. In some cases, different representations were developed for the same languages. Such disparate character sets hindered communication among computer systems. Visual Basic .NET supports the Unicode Standard (maintained by a non-profit organization called the Unic...
"About this title" may belong to another edition of this title.