Table Of ContentIntroduction
The by Example Series
How does the by Example series make you a better programmer? The by
Example series teaches programming using the best method possible. After a
concept is introduced, you’ll see one or more examples of that concept in use.
The text acts as a mentor by figuratively looking over your shoulder and show-
ing you new ways to use the concepts you just learned. The examples are
numerous. While the material is still fresh, you see example after example
demonstrating the way you use the material you just learned.
The philosophy of the by Example series is simple: The best way to teach com-
puter programming is using multiple examples. Command descriptions, format
syntax, and language references are not enough to teach a newcomer a pro-
gramming language. Only by looking at many examples in which new
commands are immediately used and by running sample programs can
programming students get more that just a feel for the language.
Who Should Use This Book
Anyone who wants to learn Visual Basic .NET should read this book. The pre-
requisites include having a basic understanding of Microsoft Windows. As long
as you understand some of the simple concepts such as files and directories,
the Internet, and applications and programs, you should not have a problem
reading this book.
The book covers some of the essential background material necessary for devel-
oping Visual Basic .NET applications. This includes an overview of the develop-
ment environment, the language itself, object-oriented concepts, database
concepts, and XML.
This book is for you if you can answer true to one of the following statements:
• I know how to use Microsoft Windows (95, 98, NT, or 2000) and want to
learn how to program.
• I am a C++ and/or Java developer and I want to learn how to develop
applications for Microsoft .NET.
• I am a Visual Basic 6.0 developer and want to learn the new Visual Basic
.NET language.
• I design and build enterprise applications and want to learn a language
that can help me.
2 Introduction
This Book’s Organization
This book is presented in six parts. The first part gives a basic overview of
Microsoft .NET and Visual Studio .NET. This sets the context for the reader
in developing Visual Basic .NET applications. The reader is then presented
with his/her first view of a very simple application. This application is then
built and executed to acquaint the user with building an application using
Visual Studio .NET.
The second part covers the Visual Basic .NET language basics. This is the
first step in understanding the language itself and covers such things as
data types, variables, and language statements.
The third part moves into object-oriented concepts. This is necessary due to
the language improvements of Visual Basic .NET. Prior versions of Visual
Basic do not require any object-oriented knowledge. With this new version,
it is a must and this book tries to present the material in order to make you
a very good Visual Basic .NET developer.
The fourth part covers user interface development using Visual Basic .NET.
This includes developing forms and controls as part of your application.
The fifth part covers data access. Most applications today deal with some
form of data. ADO.NET and XMLare popular ways of dealing with data. As
a result, these technologies are covered to show how these can be used from
Visual Basic .NET. This part also includes a basic overview of SQL, which
is used in database access provided by ADO.NET.
The sixth part covers developing Web applications using Web Forms. Here
we discuss the issues involved in developing Web applications and actually
how to do it using Visual Basic .NET.
At the end of the book, there is an appendix that covers UML(Unified
Modeling Language) in a quick crash course. The Web site includes migrat-
ing Visual Basic 6.0 to Visual Basic .NET applications, XML(eXtensible
Markup Language), and a reference of the Visual Basic .NET language.
Conventions Used in This Book
Examples are indentified by the icon shown at left of this sentence.
The source code listing is printed in a monospace font, for example:
Module Module1
Sub Main()
System.Console.Out.WriteLine(“An Example”)
EXAMPLE
End Sub
End Module
Introduction 3
Frequently, example code contains lines in bold text. These lines are in
bold to draw the reader’s attention to them. The reason for this is because
the focus of the example and the corresponding explanation is centered
around these lines. As you go through the book and the examples, pay
particular attention to reviewing the highlighted lines of code in order to
understand and absorb the meaning of each of the examples.
The output of an example is indentified by the icon shown at left of this
sentence.
NOTE
OUTPUT
Notes add more information about the material just presented. These notes clarify con-
cepts and procedures.
TIP
Tips provide shortcuts or workarounds to a particular problem.
CAUTION
Cautions provide warnings regarding things to watch out for. These should save you
time and trouble.
CHANGES FROM VISUAL BASIC 6.0
These messages indicate the changes in Visual Basic from Visual Basic 6.0 to Visual
Basic .NET.
NEW IN VISUAL BASIC .NET
These messages indicate the additional features added to Visual Basic .NET
On the Web Site
Code examples in the book, the answers to the “Checking,” “Reviewing,”
and “Applying” questions at the end of each chapter, and additional refer-
ences are available at www.quepublishing.com.
What’s Next
The book starts with an overview of Microsoft .NET and what it is all
about. Then you take a tour of the Visual Studio .NET environment so that
you can become familiar with the development environment used through-
out the book.
Part I
First Steps in Visual Studio .NET Environment
Overview of the Environment
Creating the First Application
Compiling and Running the Application
Visual Basic .NET Project Types
1
Overview of the Environment
This chapter introduces Visual Basic .NET by presenting an overview of
the development environment. The goal here is to allow you to become
acquainted with the development environment before actually jumping into
learning the Visual Basic language itself.
In this chapter, you will
• Be presented with an overview of Microsoft .NET, Visual Studio .NET,
and Visual Basic .NET
• Take a tour of Visual Studio .NET
8 Chapter 1: Overview of the Environment
Introduction
Visual Basic 6 users will see that Visual Basic .NET is not just an upgrade
from Visual Basic 6. Instead, it catapults the Visual Basic language into a
much broader arena that allows you to create many types of applications
previously too difficult (if at all possible) to implement using previous
versions of Visual Basic. If this is your first introduction to Visual Basic,
welcome aboard and enjoy the ride. Hopefully you will find Visual Basic
.NET to be a powerful language that will empower you to build world class
applications.
Visual Basic has come a long way since its infancy. Visual Basic (or VB for
short) has traditionally been a language that simplifies the development
of software applications that run on Microsoft Windows. This includes
Windows 3.1, Windows 95, Windows 98, Windows NT, and most recently
Windows 2000. The most common types of applications written in Visual
Basic have been standalone applications that run on a single computer. An
example of a simple application is the Calculator program, as shown in
Figure 1.1, that comes with Microsoft Windows. Using VB, you were able to
develop applications in a very short amount of time. Before VB, one would
need to write an application using a more complicated language, such as C
or C++, which would require a steeper learning curve and more develop-
ment time. Anew VB developer could write a simple application faster than
a moderate C developer. As a result of VB’s productivity enhancement bene-
fits, VB became a very popular language.
Figure 1.1: Asimple application.
Developers then started using VB to write applications that needed to
store data in a database. This way the application could store data in a
structured format and the data would remain on the computer when it was
turned off. The next time you turned on the computer and ran the applica-
tion you would be able to view the data again and add new data. The data-
bases started out by existing on the same computer as the application.
Later, the databases were moved to a central location on a network where
computers on the same network could talk to the same database. This way
Introduction 9
a single database could be used by many users, which meant the data could
also be shared by those users. These types of applications are called client-
server applications. The program itself is the client and the database is the
server. Figure 1.2 depicts a client-server application where an application
running on one computer communicates with a database running on
another computer.
Network
Database
User’s Computer
Figure 1.2: Aclient-server application.
As of Visual Basic 6, this client-server paradigm is still being used by
many developers. The successor to client-server is called an n-tiered appli-
cation (shown in Figure 1.3) and involves developing an application in
layers. Today’s typical application uses three distinct layers: the presenta-
tion layer, application logic layer, and data services layer. Each layer pro-
vides a specific function and is used by a layer above it. Assuming an
online e-commerce–type application, the presentation layer of an applica-
tion displays useful information to the application’s user, such as the
user’s account information and order form. The presentation layer com-
municates with the application logic layer, which provides the application
with specific functionality, such as how much to decrement the user’s
account based on the products they purchased. The application logic layer
communicates with the data services layer for reading and writing persis-
tent data, such as storing the order information in a database. Now, in
terms of an n-tiered application, each layer of an application could poten-
tially be running on a separate computer. If all the layers are running on
the same computer, the application is considered a standalone applica-
tion, or single tiered. If the application is running on three separate com-
puters (each layer running on a separate machine), the application is
considered a three-tiered application, and so on. Another way of express-
ing layers and tiers is that layers represent a logical separation of code
within an application. Atier represents where the code actually runs.
For the layers to talk to other layers running on different computers they
need a way of communicating across a network. Many Web applications fol-
low the n-tiered paradigm as part of their architecture. Examples of Web
applications are www.cnn.com, www.yahoo.com, and www.amazon.com. The com-
munication mechanism on the Microsoft Windows platform is based on
COM (Component Object Model) technologies.
