FIT 100
Lab 7: Writing and Running Your First
Visual Basic Program
Autumn 2001
·
Chapters
3 and 4 of Learn to Program with Visual Basic 6.0
OR
·
How
to Use Visual Basic, Chapters 1-3
http://library.books24x7.com/toc.asp?bkid=888
This is a link to the table of contents for the full text version of this book.
This
link will be active through
The purpose of this lab is to introduce you to the VB Integrated Design Environment (IDE) and to create a simple VB project. The IDE is the programming environment where you create applications. A VB project is the collection of files created when you are working on an application. Your Instructor will go through this environment with you in lab.
You will have time to start working on this exercise in lab. You will demonstrate your working program to your Instructor at the end of lab or at the beginning of the next one if time runs out.
Menu Bar Tool Bar ToolBox Project Window Properties Window Form Window
·
Each time you begin a project, the
default name, Project1, appears at the top of the form. To change the name,
choose
Project> Project1 Properties,
and then type in your name as the new project name.
· When working with objects in VB, it is important to realize that there are many properties associated with them. Even the form on which you design your application is an object (and has over 50 properties that can be set).
· To change the form name, click on the Properties window (or press F4) to bring it into focus. Name is the very first property. Select this property field and type in “First”.
· A Text Box
· A Label
·
(4) Command Buttons
Do NOT create a controlled array. If you
create one
command button and then copy and paste it onto the form,
the question of creating a controlled array will pop up. Say NO!
To add each object, click once on the tool in the tool box. Then go to the form and hold down the right mouse button as you “draw” the object onto the form.
·
Name the Text Box: txtATextBox
Change the Text to: This is a text box
·
Name the Label lblALabel:
Change the Caption to: This is a label
·
Name the first Command
Button: cmdClick
Change the Caption to: This is
what you click on!
·
Name the second Command
Button: cmdRed
Change the Caption to: Red!
·
Name the third Command
Button: cmdBlue
Change the Caption to: Blue!
·
Name the fourth Command
Button: cmdVisible
Change the Caption to: Visible!
·
Make the First form purple
·
Make the cmdClick
button pink (NOTE: You must first
change the Style property to Graphical)
·
Make the cmdRed
button red (NOTE: You must first change
the Style property to Graphical)
·
Make the cmdBlue
button blue (NOTE: You must first change
the Style property to Graphical)
·
Make the cmdVisible
button lilac (NOTE: You must first
change the Style property to Graphical)
· Make the lblALabel label yellow
· Click on the Run icon on the Tool Bar, or go to Run>Start… on the menu bar.
· Try clicking the cmdClick button. Notice that you can click the button, but nothing happens. That is because we have not added any code into our program so that something will happen when a user clicks the button. You will learn more about the event handler procedures that are used to control a program in the next lab.
·
Since you already named our form First, you can just click OK to save it.
·
You have named your project with
your name. Your name should come up in
the window. Click OK to save it.
· Your entire project, consisting of the form and the project space, is now saved.
*****************************************************
You will have 2 files associated with your project. One for the form and one for the project.
Always make sure that you send both of these when using FTP or using electronic turn-in.
*****************************************************
A digital clock with the
date on the window bar:
This Time.
This is a simple digital clock program with the date on the window bar. Your
goal in writing the digital clock program is to create a simple VB6 program.
The essential features are:
· Change the form name.
· Change the caption on the window bar.
· Place and use a label control.
· Place and use a timer control.
· Customize the window to be attractive.
· Save the project and form files.
Each of these features will be discussed below. The ThisTime application has the following window interface:
The VB environment allows you to change the properties for each object in the properties window. However, if you just use the properties window to make those changes (i.e. changing the background color, etc.) your program won’t be very exciting. We can attach code to a particular object event so that at run-time (when the program is executed by a user), it will react in pre-coordinated ways.
As stated above, there are many
properties and events associated with objects in VB. One of the events that occur whenever someone
opens up a form and runs it is the FORM LOAD event.
· File>New Project…(your first project, that you have saved, will now be closed. Select yes to save changes)
· Double click on Standard EXE
Private Sub Form_Load()
frmClock.Caption = Date
End Sub
Date is a
built-in global variant object that returns the date as set on the computer in
the form mm/dd/yy. When the form is loaded, the
current date will appear on the window bar.
Your code window will look similar to the above graphic. The drop down menu on the left allows you to select the object you wish to work with (your form). Objects will usually be listed by their Name property EXCEPT the form object, which will always be identified as Form.
The drop down menu on the right is the list of events and procedures that can be associated with the various objects in your program.
Notice that once you select each of these options from the list, the following text appears. This is standard in VB. By default, when you select an object and select an event procedure, the first and last lines of code that you need to have for that procedure are added in for you. You will type in all relevant code between those lines. Now, add in the code that you need from step 20.
ThisTime for the project
frmClock for the form
You will be prompted to save the form
first, and then the project. When you
have saved both, two files are created: ThisTime.vbp and frmClock.frm.
· Use the Tool Box to place a Timer somewhere on the form (it will be hidden when you run your program).
· Change the Name property of this control to tmrTime.
· Set the interval property to 1000, i.e. the timer should "go off" every 1000 milliseconds (1 second).
Private Sub tmrTime_Timer()
lblTime.Caption = Time
End Sub
REMEMBER!!!! VB adds in the start and end lines of code for the
event, so you should only have to type one line of code!!!
Time
is like Date, a
built-in global variant that returns time in HH:MM:SS format.
What happens is this:
The timer "goes off" every
second. That event causes the procedure "tmrTime" to be
called. It changes the caption of the label to the current time. Whenever
anything on the form is changed, the window is "repainted," i.e.
redisplayed. Since most of the information is unchanged and remains in a fixed
position, the clock appears to be ticking.
· Change the form’s background color.
· Shrink the window so that it nicely frames the time symbols.
· Change the background color of the label to match the background of the window.
· Change the color of the font of the label (ForeColor Property) to be attractive and to contrast nicely with the window’s background.
· Set the starting position property of the form to be the center of the screen. (Use the Form Window in the lower right of your screen)