What is Visual Basic?
Visual Basic is a tool that allows us to develop Windows (Graphic User Interface - GUI) applications. The applications have a familiar appearance to the user.
Visual Basic is event-driven, meaning code remains idle until it is called upon to respond to some event (e.g. mouse clicking, button pressing, menu selection, ...). Nothing happens until an event is detected. Once an event is detected, the code corresponding to that event (event procedure) is executed.
Stop Watch Application
1 .At the "Start-up Menu" of our Windows Desktop,
let's find where "Microsoft Visual Studio 6.0" is, and click on it.
Then we can see some shortcuts to the applications of the software suite, and
"Microsoft Visual Basic6.0" is one of them and it is also our
"target software" right now, let's select it.
2. We now at the main screen of Visual Basic 6.0 with its
"New Project" window. Let's click on the "New" tab and
select "Standard EXE" icon.
3. Before we go on, let's consider the components of the
toolbar of Visual Basic 6.0. Properties
window, Run and Save project are what we have to focus on now.
4 .Controls are the genius tools that can be attached by any
codes that can control any events such as clicking mouse or pressing key. Now
the "Command Button" and the "Label" are the controls that
we are going to use.
5. Visual Basic programming begins with a form which has
been named "Form1" by default. Visual Basic form simulates itself as
platform which can receive many kinds of objects that created by the controls.
Any object has its properties that has been shown in the properties window.
6 .Here we go on creating a design job like the following
picture.
- Using the "Command Button" control
to draw the three sequence command buttons, Command1, Command2 and Command3.
- Using the "Label" control to draw
the six sequence labels, Label1,
Label2, Label3, Label4, Label5 and Label6
7.Click on "Form1", we can see its properties,
rename it with "frmStopWatch" (frm is a pefix which comes from
"form"). And change its caption to "Stop Watch
Application".
8. Click on "Command1", yes we are about to specify
the properties of this object. Rename it with "cmdStart" (cmd is a
prefix which comes from "command button") and also refill its caption
with "&Start Timing" (& is a prefix of the key letter that a
user can press on this key together with the "alt" key instead of
click on this command button).
9 .Do it the same way as the previous step.
10 .Do it the same way as the previous step.
11 .Change only the captions of Label1, Label2 and Label3
according to the following picture.
12. Change the properties of the other last three labels,
"Label4", "Label5" and "Label6" by renaming them
to "lblStart", "lblEnd" and "lblElapsed" and
erase their captions until they are blank.
13. Now we have just already designed and configured all of
related objects, the next step of us is coding our program. Let's click on the
menu-bar at the "View" command tab, then select the "Code"
sub-command, the view-code window will show up. Yes, we are going to enter our
source codes of our application here.
14. The first set of source codes is about the declarations.
There will be the "(General)" at the left-top of the view-code window
and the "(Declarations)" at the right-top. We have to type four lines
of our following source codes.
15. This step is about attaching our source code to a
control object. The "cmdStart" is a command button we are going to
attach the source code. Let's double click on this command button, yes, this
action could bring us to a module or subprogram that could be driven by an
event, _click ( ), that means this subprogram could work when this command
button was clicked on.
What is about this source code? It begins with assigning the recent time
value (Now) to the variable "StartTime". Then the method "Caption"
stipulates that the label "lblStart" can show up data from the
variable "startTime" with the "hh:mm:ss:" format.
16 .This step is similar to the previous but it turns to the
"cmdEnd" command button. But it creates the expression which assigns
the variable "ElapsedTime" with the difference of the variable
"EndTine" and the variable "StartTine".
17 .This is the end of application with the only amazing
word "End"
18 .Congratulation to our tough project!. This is the output
of our input and process. Yes, it is the "Stop Watch Application" of
us.
19 .We have to make our project to an independent
application. Click on the
"File" command at the menubar then select the
"Make..to..EXE" subcommand.
By Tanunya Sophon m.2/8 no.35
