Visual Basic.NET How to Program (PDF)

Chapter 1 Introduction to Computers, Internet and Visual Basic .NET 25
Chapter 16—Graphics and Multimedia
In this chapter, we discuss GDI+ (an extension of the Graphics Device Interface—GDI),
the Windows service that provides the graphical features used by .NET. The extensive
graphical capabilities of GDI+ can make programs more visual and fun to create and use.
We discuss Visual Basic .NET’s treatment of graphics objects and color control, and we
discuss how to draw arcs, polygons and other shapes. We use various pens and brushes to
create color effects and include an example demonstrating gradient fills and textures. This
chapter introduces techniques for turning text-only applications into exciting, aesthetically
pleasing programs that even novice programmers can write with ease. The second half of
the chapter focuses on audio, video and speech technology. We discuss adding sound, video
and animated characters to programs (primarily using existing audio and video clips). You
will see how easy it is to incorporate multimedia into Visual Basic .NET applications. This
chapter introduces an exciting technology called Microsoft Agent for adding interactive animated
characters to a program. Each character allows users to interact with the application,
using natural human communication techniques, such as speech. The agent characters accept
mouse and keyboard interaction, speak and hear (i.e., they support speech synthesis and
speech recognition). With these capabilities, your applications can speak to users and can
even respond to their voice commands!
Chapter 17—Files and Streams
Imagine a program that could not save data to a file. Once the program is closed, all the
work performed in the program is lost forever. For this reason, this chapter is one of the
most important for programmers who will be developing commercial applications. We explain
how to input and output streams of data from and to files, respectively. We present
how programs read and write data from and to secondary storage devices (such as disks).
A detailed example demonstrates these concepts by allowing the user to read and write
bank account information to and from files. We introduce those classes and methods in Visual
Basic .NET that help perform file input and output conveniently—they demonstrate
the power of object-oriented programming and reusable classes. We discuss benefits of sequential
files, random-access files and buffering. This chapter is crucial for developing Visual
Basic .NET file-processing applications and networking applications, which also use
the techniques in this chapter to send and receive data.
Chapter 18—Extensible Markup Language (XML) 7
The Extensible Markup Language (XML) derives from SGML (Standardized General
Markup Language), which became an industry standard in 1986. Although SGML is employed
in publishing applications worldwide, it has not been incorporated into mainstream
computing and information technology curricula because of its sheer size and complexity.
XML is an effort to make SGML-like technology available to a much broader community. It
was created by the World Wide Web Consortium (W3C) for describing data in a portable format,
is one of most important technologies in industry today and is being integrated into almost
every field. XML differs in concept from markup languages such as the HyperText
Markup Language (HTML). HTML is a markup language for describing how information is
rendered in a browser. XML is a language for creating markup languages for virtually any
7. The reader interested in a deeper treatment of XML may want to consider our book, XML How to
Program.