Chapter 1
Visual Basic at Work
Welcome to Visual Basic! You possess one of the most powerful and enjoyable Windows
development tools available today. Visual Basic really is fun, as you'll see throughout
this 24-hour tutorial. In this hour you will become familiar with the big picture
of Visual Basic 5.
The highlights of this hour include
- What Visual Basic does
- How to start Visual Basic
- How to stop Visual Basic
- When to use the different Visual Basic windows
- How the system windows work together for you
Whats Visual Basic
About?
Controls are tools on the Toolbox window that you place on a form to interact
with the user and control the program flow.
Microsoft Visual Basic 5.0, the latest and greatest incarnation of the old BASIC
language, gives you a complete Windows application development system in one package.
Visual Basic (or VB, as we often call it) lets you write, edit, and test Windows
applications. In addition, VB includes tools you can use to write and compile help
files, ActiveX controls, and even Internet applications.
New Term: A program is a set of instructions
that make the computer do something such as perform accounting. (The term program
is often used synonymously with application.)
Visual Basic is itself a Windows application. You load and execute the VB system
just as you do other Windows programs. You will use this running VB program to create
other programs. VB is just a tool, albeit an extremely powerful tool, that programmers
(people who write programs) use to write, test, and run Windows applications.
New Term: A project is a collection of files
you create that comprises your Windows application.
Although programmers often use the terms program and application interchangeably
(as will be done throughout this 24-hour course), the term application seems to fit
the best when you're describing a Windows program because a Windows program typically
consists of several files. These files work together in the form of a project. The
project generates the final program that the user loads and runs from Windows by
double-clicking an icon or by starting the application with the Windows Start menu.
New Term: An application is a collection
of one or more files that compile into an executable program.
The role of programming tools has evolved over the past 45 years along with computer
hardware. A programming language today, such as Visual Basic, differs greatly from
programming languages of just a few years ago. The visual nature of the Windows operating
system requires more advanced tools than were available a few years ago. Before windowed
environments, a programming language was a simple text-based tool with which you
wrote programs. Today you need much more than just a language; you need a graphical
development tool that can work inside the Windows system and create applications
that take advantage of all the graphical, multimedia, online, and multiprocessed
activities that Windows offers. Visual Basic is such a tool. More than a language,
Visual Basic lets you generate applications that interact with every aspect of today's
Windows operating systems.
NOTE: Although Visual Basic
is a comprehensive programming tool, VB retains its BASIC language heritage. Designers
in the late 1950s developed the BASIC programming language for beginning programmers.
BASIC was easier to use than other programming languages of the time, such as COBOL
and FORTRAN. Microsoft never forgot VB's roots when developing Visual Basic. Newcomers
to programming can learn to create simple but working Windows programs in just a
short time. You will be using Visual Basic to write Windows programs before the next
hour is complete.
New Term: Wizards are question-and-answer
dialog boxes that automate tasks.
-
New Term: A compiler is a system that
converts the program you write into a computer-executable application.
If you've taken a look at Visual Basic in the past, you'll be amazed at today's Visual
Basic system. VB now sports a true compiler that creates standalone runtime .EXE
files that execute more quickly than previous VB programs. VB also includes several
wizards that offer step-by-step dialog box questions that guide you through the creation
of applications. VB's development platform, a development environment called the
Developer Studio, now supports the same features as the advanced Visual C++ and Visual
J++ compilers. Therefore, once you learn one of Microsoft's Visual programming products,
you will have the skills to use the other language products without a long learning
curve ahead of you.
New Term:The Developer Studio is Visual Basic's
development environment.
Languages
Programming languages today are not what they used to be. The language itself
has not gotten less important; rather, the graphical interfaces to applications have
gotten more important.
A computer cannot understand any person's spoken language. A spoken language,
such as Italian or English, is simply too general and ambiguous for computers to
understand. Therefore, we must adapt to the machine and learn a language that the
computer can understand. VB's programming language is fairly simple and uses common
English words and phrases for the most part. The language is not ambiguous, however.
When you write a statement in the Visual Basic language, the statement never has
multiple meanings within the same context.
New Term: Code is another name for
the programming statements you write.
As you progress through the next 24 hours, you will learn more and more of the Visual
Basic language's vocabulary and syntax (grammar, punctuation, and spelling rules).
You will use the VB programming language to embed instructions within applications
you create. All the code you write (code is the program's instructions) must work
together to instruct the computer. Code is the glue that ties all the graphics, text,
and processes together within an application. Code tells a checkguide application,
for example, how to be a checkguide application and not something else. The program
code lets the application know what to do given a wide variety of possible outcomes
and user actions.
Visual Basics Three
Editions
Visual Basic 5 comes in three flavors: the Standard Edition, the Professional
Edition, and the Enterprise Edition. Although this guide primarily deals with the
Professional Edition, the Standard Edition is called the learning edition and provides
the least expensive approach to using Visual Basic. The Standard Edition gives you
a complete development environment, programming language, and many of the same tools
the other editions offer. If you use the Standard Edition, you have a powerful programming
tool. Some people develop only with the Standard Edition and never need anything
else. Although this course targets the Professional Edition in an attempt to hit
common ground, you will be able to utilize virtually the entire 24-hour course if
you use the Standard Edition; you will find additional tools in the Standard Edition
that this course does not even get to.
The Professional Edition offers a few more tools, including extra ActiveX add-in
tools, better Internet programming support, a help file compiler, and improved database
access tools. Most professional programmers use the Professional Edition.
The Enterprise Edition provides the client/server programmer with extended tools
for remote computing and application distribution. Microsoft enhanced VB's performance
for Enterprise Edition users working in a networked, distributed environment.
TIP:Most programmers need
only the Standard or Professional Edition. The Enterprise Edition is aimed at developers
who write network-intensive client/server applications. The Enterprise Edition is
enhanced to aid such programmers who work within the special client/server environments.
If you want to create your own ActiveX controls, you will need the VB 5 Custom
Control Edition that comes with the Professional and Enterprise Editions. If you
use the Standard Edition, you're still in luck because the CD-ROM that comes with
this guide includes the VB 5 Custom Control Edition, which you can add to your Visual
Basic folder and use to create ActiveX controls. Hour 21, "Visual Basic and
ActiveX," describes more about the VB 5 Custom Control Edition.
The VB Programming
Process
When you want to use Visual Basic, you'll follow these basic steps:
- 1. Start Visual Basic.
2. Create a new application or load an existing application. When you create
a new application, you might want to use Visual Basic's VB Application Wizard to
write your program's initial shell, as you'll do in the next hour.
New Term: A bug is a program error
that you must correct (debug) before your program executes properly.
- 3. Test your application with the debugging tools Visual Basic supplies.
The debugging tools help you locate and eliminate program errors (called bugs) that
can appear despite your best efforts to keep them out.
4. Compile your program into a final application.
5. Quit Visual Basic.
6. Distribute the application to your users.
Rarely will you perform all these steps sequentially in one sitting. The six steps
are not sequential steps, but stages that you go through and return to before completing
your application.
Starting Visual Basic
You start Visual Basic from the Windows Start menu. The Visual Basic development
environment itself usually appears on a submenu called Microsoft Visual Basic 5.0,
although yours might be called something different due to installation differences.
You will see additional programs listed on the Microsoft Visual Basic 5.0 submenu,
but when you select Visual Basic 5.0 from the submenu, Visual Basic loads and appears
on your screen.
On most systems, Figure 1.1's dialog box appears as soon as you start Visual Basic.
The dialog box lets you start the VB Application Wizard, edit an existing VB project,
or select from a list of recent projects you've worked on, depending on the dialog
box tab you click.
As you can see at the bottom of the dialog box, you don't have to see the dialog
box every time you start Visual Basic. If you click the option labeled Don't show
this dialog box in the future, Visual Basic will not display the opening dialog box
when you start Visual Basic.
Figure
1.1. The New Project dialog box often
appears when you start VB.
NOTE:If you decide not to
show the New Project dialog box for subsequent start-ups, you will still be able
to access the dialog box's operations from VB's File menu.
Once you close the dialog box, the regular Visual Basic screen appears. As Figure
1.2 shows, VB's opening screen can get busy! Figure 1.2 shows the Visual Basic development
environment, the environment with which you will become intimately familiar soon.
From this development environment you will create Windows programs.
Figure
1.2. VB's screen looks confusing
at first.
Although the screen can look confusing, you can fully customize the Visual Basic
screen to suit your needs and preferences. Over time, you will adjust the screen's
window sizes and hide and display certain windows so that your Visual Basic screen's
start-up state might differ tremendously from that of Figure 1.2.
New Term: A dockable window is a window that
you can resize and move to the sides of the screen and connect to other windows.
TIP:Most of VB's windows are
sizable and dockable, meaning you can connect them together, move them, and hide
them.
This hour's section titled "Mastering the Development Environment" explains
the parts of the development environment and how to maneuver within it.
Stopping Visual
Basic
You'll exit from Visual Basic and return to Windows the same way you exit most
Windows applications: Select File|Exit, click Visual Basic's main window close button,
press Alt+F4, or double-click VB's Control menu icon that appears in the upper-left
corner of the screen.
If you have made changes to one or more files within the currently open project
(remember that a project is the collection of files that comprise your application),
Visual Basic gives you one last chance to save your work before quitting to Windows.
WARNING: Never
power-off your computer without completely exiting Visual Basic, or you might lose
some or all of your work for the current session.
Mastering the Development
Environment
Learning the ins and outs of the development environment before you learn Visual
Basic is somewhat like learning the parts of an automobile before you learn to drive;
you might have a tendency to skip the terms and jump into the foray. If, however,
you take the time to learn some of the development environment's more fundamental
principles, you will be better able to learn Visual Basic. You then will be more
comfortable within VB's environment and will have a better understanding of the related
words when subsequent lessons refer to the windows and tools in the development environment.
Figure 1.3 shows the Visual Basic development environment with many of the more
important screen components labeled. As you can see from the menu and toolbar, Visual
Basic looks somewhat like other Windows programs on the market. Many of Visual Basic's
menu bar commands work just as they do in other applications such as Microsoft Word.
For example, you can select Edit|Cut and Edit|Paste to cut and paste text from one
location to another. These same menu bar commands appear on almost every other Windows
program on the market today.
Figure
1.3. Getting to know the development environment.
NOTE: Figure 1.3 shows
only a portion of the development environment's windows and components. As you need
additional tools, such as the Menu Editor, this tutorial describes how you access
those tools.
Standards: The Menu
Bar and Toolbar
Visual Basic's menu bar and toolbars work just as you expect them to. You can
click or press a menu bar option's hotkey (for example, Alt+F displays the File menu)
to see a pull-down list of menu options that provides either commands, another level
of menus, or dialog boxes. Many of the menu options have shortcut keys (often called
accelerator keys) such as Ctrl+S for the File|Save option. When you press an accelerator
key, you don't first have to display the menu to access the option.
The toolbar provides one-button access to many common menu commands. Instead of
selecting Edit|Paste, for example, you could click the Paste toolbar button. As with
most of today's Windows applications, Visual Basic supports a wide range of toolbars.
Select View|Toolbars to see a list of available toolbars. Each one that is currently
showing will appear with a checkmark by its name.
TIP:As you begin to work with
Visual Basic, pay attention to the form location and form size coordinates at the
left of the toolbar buttons. These measurements, in twips (a twip is 1,440th of an
inch, the smallest screen measurement you can adjust), determine where the Form window
appears and its size. Twip values usually appear in pairs. The first location value
describes the x-coordinate (the number of twips from the top of the screen) and the
second value describes the y-coordinate (the number of twips from the left of the
screen), with 0,0 indicating the upper-left corner of the screen. The first size
value describes the width of the form, and the second size value describes the height
of the form. Therefore, the size coordinate pair 1000,3000 indicates that the Form
window will be 1,000 twips wide and 3,000 twips tall when the program runs. As you'll
learn in the next section, the Form window is the primary window for the applications
you write. The location and size coordinates describe the form's location and size
when you run the application.
The Form Window:
Where It All Happens
The Form window is your primary work area. Although the Form window first appears
small relative to the rest of your screen, the Form window comprises the background
of your application. In other words, if you write a Windows-based calculator with
Visual Basic, the calculator's buttons all reside on the Form window and when someone
runs the calculator, the calculator that appears is really just the application's
Form window with components placed there and tied together with code.
NOTE:You will not see program
code on the Form window. The Form window holds the program's interactive objects,
such as command buttons, labels, text boxes, scrollbars, and other controls. The
code appears elsewhere in a special window called the Code window. The Code window
does not appear in Figure 1.3, but you can select View|Code to see the Code window.
A Code window is little more than a text editor with which you write the programming
statements that tie together the application.
Consider the sample program running in Figure 1.4's window. The window shows a
simple dialog box with a few options, text boxes, and command buttons.
Figure
1.4. A simple dialog box produced from
a running Windows program.
The programmer who created Figure 1.4's dialog box did so by opening a Form window,
adding some controls (the items on the Form window that interact with the user--sometimes
called tools), and tying the components together with some Visual Basic language
code. That's exactly what you will do when writing simple and complex Visual Basic
applications. You will begin with a blank Form window and add controls to the Form
window such as options and command buttons. Perhaps your application might even require
multiple Form windows.
NOTE: Some applications,
such as Word, allow for several Form windows in a special mode called MDI (multiple-document
interface) in which you can open multiple data documents within the same application.
An application that requires only a single data window is called an SDI (single-document
interface) application, such as the Windows Notepad application that lets the user
open only one data document at a time. SDI applications might support multiple forms;
however, these forms do not hold multiple data files but only provide extended support
for extra dialog boxes and secondary work screens.
Compare Figure 1.4 with Figure 1.5. As you can see, Figure 1.5 shows the same
application in the VB development environment. Figure 1.5 shows the application in
its design-time state as opposed to its runtime state, which is shown in Figure 1.4.
It is during design time that you design, create, edit, and correct the application.
When you or another user runs the application, the results of your work can be seen.
Source program is code, forms, menus, graphics, and help files that you create
and edit to form the project (also called source code).
The parts of the application that you create, such as the forms, the code, and
the graphics that you prepare for output, comprise the source program. When you or
another user compiles or runs the source program, VB translates the program into
an executable program. You cannot make changes directly to an executable program.
If you see bugs when you run the program, you must change the source application
(which might contain multiple files in the project) and rerun or recompile the source.
Figure
1.5. The dialog box shown inside VB's
development environment.
The Toolbox Supplies
Controls
The toolbox contains the controls that you place on the Form window. All of Figure
1.5's controls appear on the toolbox. You will learn in the next hour's lesson how
to place toolbox controls on the Form window. The toolbox never runs out of controls;
if you place a command button on the Form window, another awaits you on the toolbox,
ready to be placed also.
Figure 1.6 names every tool that appears on the standard Toolbox window. These
are called the intrinsic controls because all three editions of VB support these
standard tools. You can add additional controls to the toolbox as your needs grow.
Some extra tools come with all three editions of VB, but these extra tools do not
appear on the Toolbox window until you add them through the Project|Components menu
option. If you use the Professional or Enterprise Editions, you will be able to add
extra controls that don't appear in the Standard Edition's collection of intrinsic
and extra controls.
Figure
1.6. The dialog box shown inside VB's
development environment.
The Form Layout
Window Places Forms
The Form Layout window displays the initial position and relative size of the
current form shown in the Form window. For example, look back at Figure 1.5 to see
the Form Layout window. The application being studied is a multiple-form application.
The form with the title Text Box Properties is just one of several forms. The Form
Layout window always shows where the form appears in the current Form window. If
you want the form to appear at a different location from the current position, you
can move the form inside the Form Layout window to move the form's appearing position
when the user runs the application.
TIP: Notice that the
form location indicators, to the right of the toolbar buttons, change when you move
the form in the Form Layout window.
This guide generally does not show the Form Layout window in figures to give more
room to the Form window and its contents. You can display the Form Layout window
from the View menu, and you can hide the Form Layout window by clicking its window
close button.
The Project Explorer
Window
The Project Explorer window, often called the Project window, gives you a tree-structured
view of all the files in the application. Microsoft changed the formal name from
Project window to Project Explorer window between versions 4 and 5 to celebrate the
resemblance of the window to the typical Explorer-like tree-structured file views
so prevalent in Windows 95 and NT. You can expand and collapse branches of the view
to get more or less detail.
The Project Explorer window displays forms, modules (files that hold supporting
code for the application), classes (advanced modules), and more. When you want to
work with a particular part of the loaded application, double-click the component
in the Project window to bring that component into focus. In other words, if the
Project Explorer window displays three forms and you need to edit one of the forms,
locate and double-click the form name in the Project window to activate that form
in the Form window. Figure 1.7 shows a Project Explorer window that contains several
kinds of files.
Figure
1.7. The Project window keeps track of
the project's components.
WARNING: If you
add a help file to your application, the Project window does not display the help
file.
The Properties Window
New Term: Properties are detailed descriptive
information about a control.
A different list appears in the Properties window every time you click over a different
Form window tool. The Properties window describes properties (descriptive and functional
information) about the form and its controls. Many properties exist for almost every
object in Visual Basic. The Properties window lists all the properties of the Form
window's selected control.
Help Is at Your
Fingertips
New Term: guides Online are electronic
guides about Visual Basic for the Visual Basic programmer.
Visual Basic's online help system is one of the most advanced on the market. When
you want help with a control, window, tool, or command, press F1. Visual Basic analyzes
what you are doing and offers help. In addition, Visual Basic supports a tremendous
help resource called guides Online. When you select guides Online from the Help menu,
Visual Basic displays a tree-structured view of guides about Visual Basic that you
can search and read. The online help extends to the Internet as well. If you have
an Internet connection, you can browse the latest help topics by selecting Help|Microsoft
on the Web.
Summary
This hour quickly introduced you to Visual Basic. Perhaps you already can see
that Visual Basic is more than it first appears. Programmers use Visual Basic to
create extremely advanced Windows applications. Now that you understand VB's purpose
and how to start and stop VB, you're ready to jump right in.
The next hour describes a sample application that comes with Visual Basic so you
can get a better picture of how Visual Basic's components work together.
Q&A
- Q Must I learn a new language to use Visual Basic?
A Visual Basic is more than just a programming language. Nevertheless, learning
VB's language portion is integral to writing advanced applications. Fortunately,
the Visual Basic programming language is one of the easiest programming languages
in existence. The language is simple but powerful because Microsoft based Visual
Basic's language on BASIC, a beginner's language. VB's simplicity does not translate
to inability, however. Visual Basic is one of the most powerful Windows programming
languages on the market and supports advanced programming techniques.
Q How can I master the complicated-looking development environment?
A The Developer Studio might look complicated, but only because you are new to
the development environment. The development environment is little more than a collection
of windows. As you learn more about Visual Basic, you will learn which windows you
need and when you need them; you can close the other windows. The Developer Studio
development environment is a development platform Microsoft has integrated into most
of its language products, including Visual C++ and Visual J++. Therefore, once you
master the development environment, you will already understand the other language's
development environment as well.
Workshop
The quiz questions and exercises are provided for your further understanding.
See Appendix C, "Answers," for answers.
Quiz
- 1. What is the purpose of Visual Basic?
2. How have programming languages changed over the years?
3. What programming language is Visual Basic based on?
4. Which Visual Basic development environment window forms the background for
the applications you develop?
5. What are the three editions of Visual Basic and how do they differ?
6. What is the difference between the Form window and the Form Layout window?
7. How can you tell the width and height of the Form window?
8. True or false: All the tools you find on the Toolbox window when you start
Visual Basic are the intrinsic controls.
Exercise
Start Visual Basic and select various options from the View window. You will see
several new windows open. Look through the menu options and click on any scrollbars
you see. Don't save anything when prompted. Double-click over tools on the toolbox
to see different tools appear on the Form window. Move the tools away from the center
of the window to see more of them at one time. As you click on different tools in
the Form window, watch the Properties window change to reflect the current tool's
properties.
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