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As a C and C++ programmer who is slowly learning the art of writing
Windows applications I had heard of Microsoft's Visual Basic, and
dismissed it as a serious programming tool.
BASIC was fine when I was in high school playing with a Commodore 64, and
later playing with QBasic on a PC, but as an adult doing graduate
work in computer science I have been firmly told to set aside the
things of childhood and use C. But curiosity got the better of me
so I tore the shrink-wrap from Microsoft Visual Basic 3.0 and
installed it to see what, if anything, the language is good for.
How Visual Basic Works
In addition to the sin of using BASIC for coding, Visual Basic
earns the contempt of many serious programmers for being easy to use.
For cripes's sake, you draw programs as much as write code!
VB programs are built around two major types of components, "forms"
and "code modules". Forms are windows, whether they're simple dialog
boxes or full windows with menus. You choose various controls—text
boxes, list boxes, radio buttons, etc.—and place them on the form,
resizing and repositioning them easily by dragging and dropping. Objects
such as controls, windows, and labels have properties like color, text,
and border style, which are set in the properties window.
If you keep the properties window open while you work it changes,
listing only those properties which apply to the currently highlighted
object.
Most properties are analogous to attributes which are changed in
a C or C++ program by passing arguments to functions, or by filling out
structures. For instance, changing the mouse pointer from an arrow to an
I beam as it passes over a text box is as easy as opening a drop-down
list of pointer types in the properties window for the text box. Many
object properties can also be altered at runtime by code.
You can write code to be executed when events relating to the
object happen. In C you have to write a message loop which calls the
appropriate function when an event such as a double click occurs, then
write the function. In Visual Basic each form has its own code module
which can be opened in a separate window. From this window you select
any object on the form and an event which can happen to it, then add and
edit the code to execute when the event occurs. This is a handy way to
keep your code organized, although some programmers dislike having their
code broken up into so many little files. It's easy to forget exactly
where you put a certain piece of coding you want to reuse.
In addition to the code module associated with each form, you can
build common code modules with routines that can be called from any
other form. This way you can write code that can be executed by a menu
command, button, or double click in a list box a single time and call it
from the procedures for those objects, rather than duplicating code.
Menus are a snap to implement in Visual Basic. There is a Menu
Design window to build the menu structures, complete with access keys,
shortcut keys, and separators. The VB manual describes how to build menu
control arrays to have a list of menu items that changes at runtime,
such as currently open windows or the last four files loaded. Menus can
be controlled at runtime with BASIC code, disabling items, adding check
marks, or even hiding or addingselections. It's easy to add code to menu
items to define what happens when the user chooses them.
Power at Your Fingertips
What impressed me most about Visual Basic is how easy it is to do
complicated and powerful things. The sample programs in the Programmer's
Guide, the starting point of the five manuals in the VB Professional
box, are amazing in how simply they tap the power of Windows. In Chapter
2, "Your First Visual Basic Application", the reader is instructed to
draw five controls on a form, change a couple of properties for four of
the controls, and write eight lines of code. The result is an
application which allows you to navigate through your drives and
directories using typical Windows file dialog controls, and choose a
bitmap, icon or Windows metafile, which will then be displayed. This
took maybe five minutes going slowly through the instructions, and I
spent half an hour playing with my new app, browsing the bitmaps and
icons that come with Visual Basic.
The text editor in chapter 4 takes a little longer to put together,
but again the power that comes out of a small amount of work is amazing.
You draw a large text box which can be used to edit a document. If the
user selects text to copy to the Windows clipboard you can carry this
out with a single line of code—"Clipboard.SetText = txtEdit.SelText".
"Clipboard" is a predefined object which refers to the Windows
clipboard, and ".SetText" means put the following text into the
clipboard. "TxtEdit" is the text box control on the window, and the
".SelText" property refers to whatever text the user has highlighted by
dragging the pointer over it. The only one of these four things which
isn't predefined in VB is txtEdit, which you actually have to draw on a
form and name yourself (a whole 10 seconds work if you're slow).
Although Visual Basic 3.0 isn't quite up to the same standards of
ease of use as more recent Microsoft products such as Word 6.0 and
Access 2.0, it's still refreshingly useable. Like most users, I don't
bother to pull out the manual every time I want to do something new with
an application. Instead I just try doing it, guessing how to make it
work. I then wait for a dialog box to pop up with some information that
gives me a hint about the right way to do it. Visual Basic startled me
many times by never popping up the dialog—it worked the way I guessed it
would.
When I say VB doesn't measure up to more recent Microsoft products,
I'm referring to small touches of usability that I found in Access and
was disappointed not to find in VB. A minor example is the ability to
double-click on the sizing control of a text label and have it snap to
fit the text. A major example is help labels on the button bar. The
current trend in Windows applications is little yellow boxes that pop up
with descriptive labels if you let the pointer rest on a button for a
moment. Visual Basic 3.0 doesn't give any indication what the buttons
do, so you have to use trial and error. The product also lacks the
Wizards found in recent Microsoft products, except for the Setup Wizard
described below.
More Power
Visual Basic gives programmers access to pretty much anything you
could conceive of doing in Windows. Multiple Document Interface (MDI)
applications are easy to implement. VB applications can tie into
databases including Access, Paradox, Btrieve, dBase and FoxPro, which
makes it ideal for custom designing front ends to large databases. DDE
and OLE functionality offer considerable power for linking a VB
application to other DDE or OLE enabled Windows programs.
The usefulness of Visual Basic is greatly extended by the ability
to call procedures in DLL's. Programmers can combine the power,
efficiency and speed of whatever language they prefer with the easy user
interface design of VB by writing the meat of the application into DLL
files, then calling the appropriate functions from Visual Basic. This is
a must for really huge projects, since Visual Basic projects have limits
on the number of objects and procedures, and procedure size, among other
things.
Most of these limits are large enough to avoid cramping all but
the very largest applications, and the documentation spells out the
limitations of Visual Basic applications in detail.
Visual Basic 3.0 Professional Edition ships with gobs of icons,
over 450, including many which are useful for button bars. It also comes
with a Setup Wizard and Setup Toolkit. The wizard, like other Microsoft
wizards, consists of a series of dialog boxes which ask for information
about the options you would like. It then creates master copies of
distribution floppies. The toolkit gives you more flexibility than the
Wizard, since you can customize the setup program the user will use to
install and configure your software, and use your own compression
utility.
The Docs
The Professional Edition of Visual Basic comes with five books. The
Programmer's Guide is the main manual for learning to use the language,
covering everything I've discussed so far. The Language Reference lists
Visual Basic commands, objects, properties, methods and events, and will
quickly take over from the Programmer's Guide as the book to keep handy
when you get past the learning stage and into serious productivity,
although most of the information is available from the on-line help.
The final manual is the Microsoft Office Developer's Kit, which
explains how to combine Visual Basic with Microsoft Office applications
to design and program integrated solutions.
So What?
Visual Basic should be of interest to a pretty broad spectrum of
programmers and would-be programmers. People new to programming will be
able to get up and running pretty quickly, although I'd advise that you
be pretty familiar with the way Windows works before tackling it. If
you're interested in becoming a serious programmer you'd be well advised
to learn a regular, procedural language before tackling VB, since the
visual programming paradigm uses an entirely different way of looking at
computer programs.
Anybody with previous programming experience, especially with other
Microsoft BASIC products such QBasic, will hit the ground running. I've
worked with several languages, although not at a professional level, and
was able to build the rudiments of a mail reading program that reads QWK
format mail from BBS's in less than two days after installing Visual
Basic. VB is especially useful to programmers who've worked with DOS or
UNIX but are new to message driven GUI platforms. It's a quick way to
pick up the concepts of how Windows works before learning how to write
Windows apps in C or C++.
Why would a serious programmer want to use Visual Basic? To get
applications up and running quickly. Windows applications can be written
with Visual Basic in a fraction of the time it would take in C or C++.
When deciding whether to write an application in C++ or VB I would
consider not only the time, but how much the application has to do
besides interface oriented activities. If the app is mostly involved in
reading and presenting data and getting and writing input from users
Visual Basic is perfect. If user interaction is very minor—if the app
will spend a lot of time processing data, for example—I'd recommend
writing it in C or C++, or writing DLL's in C or C++ to be called from a
VB interface.
Most properties are analogous to attributes which are changed in
a C or C++ program by passing arguments to functions, or by filling out
structures. For instance, changing the mouse pointer from an arrow to an
I beam as it passes over a text box is as easy as opening a drop-down
list of pointer types in the properties window for the text box. Many
object properties can also be altered at runtime by code.
You can write code to be executed when events relating to the
object happen. In C you have to write a message loop which calls the
appropriate function when an event such as a double click occurs, then
write the function. In Visual Basic each form has its own code module
which can be opened in a separate window. From this window you select
any object on the form and an event which can happen to it, then add and
edit the code to execute when the event occurs. This is a handy way to
keep your code organized, although some programmers dislike having their
code broken up into so many little files. It's easy to forget exactly
where you put a certain piece of coding you want to reuse.
In addition to the code module associated with each form, you can
build common code modules with routines that can be called from any
other form. This way you can write code that can be executed by a menu
command, button, or double click in a list box a single time and call it
from the procedures for those objects, rather than duplicating code.
Menus are a snap to implement in Visual Basic. There is a Menu
Design window to build the menu structures, complete with access keys,
shortcut keys, and separators. The VB manual describes how to build menu
control arrays to have a list of menu items that changes at runtime,
such as currently open windows or the last four files loaded. Menus can
be controlled at runtime with BASIC code, disabling items, adding check
marks, or even hiding or addingselections. It's easy to add code to menu
items to define what happens when the user chooses them.
Most of these limits are large enough to avoid cramping all but
the very largest applications, and the documentation spells out the
limitations of Visual Basic applications in detail.
Visual Basic 3.0 Professional Edition ships with gobs of icons,
over 450, including many which are useful for button bars. It also comes
with a Setup Wizard and Setup Toolkit. The wizard, like other Microsoft
wizards, consists of a series of dialog boxes which ask for information
about the options you would like. It then creates master copies of
distribution floppies. The toolkit gives you more flexibility than the
Wizard, since you can customize the setup program the user will use to
install and configure your software, and use your own compression
utility.
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