CSE/IMT 100: Assignment
8
Writing and Running Your First Visual Basic Program
The purpose of this lab is to introduce you to the VB Integrated
Design Environment (IDE) and how 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 TA
will go through this environment with you in lab, but to have a better
understanding of the terminology and windows in the IDE, you are strongly
encouraged to read chapters 2 and 4 of your Visual Basic 6 book. There are a
lot of concepts introduced in these chapters, but if you pay close attention
you can get up to speed with the VB basics in no time.
You will have time to start working on this exercise in lab
on Tuesday/Wednesday, October 10/11. Your objective is to demonstrate your
program to your TA in the Thursday/Friday labs.
- Open
up VB6. On most computers in the library it can be found from the Windows
“Start” button by selecting “Programs” and “Microsoft Visual Studio
6.0”. When you start VB you will be
presented with a “New Project” dialog box. You want the default project
type, “Standard EXE”.
- You
will be presented with the IDE, which typically contains the menu bar, the
tool bar, the toolbox, and three types of windows: Form, Project, and
Properties.
- Rename
your project: 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.
- Rename
the form: when you are working with objects in VB, it is important to
realize that there are lots of 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 select F4) to bring it into focus. Name is the very
first property. Select this property field and type in “First”.
- Notice
that the title bar of the form still says “Form1”. To change this text,
select the Caption property and type in “My First VB Program”.
- Before
we proceed, save your project to a floppy disk. Notice that you are
prompted to save not just the form, but the project as well.
- Let’s
make this form do something. We could just set other properties of the
form, but it will be more interactive if we add some controls. Let’s add a
button. To add a button, select CommandButton from the toolbox,
then place your cursor over the form, hold down the left mouse button, and
draw a button. When you release the mouse button, your command button
should appear.
- Notice
that when your button appears, its properties are now in the Properties
window. This is because it has focus. Select the caption property of the
button and type “Blue” Select the name property and type “cmdBlue”.
- Repeat
steps 7 and 8, creating another button with the caption “Red” and the name
“cmdRed”.
- Although
we have buttons on our form, we haven’t instructed them to do anything
yet. Try running your program. While there are several ways to run a
program from the IDE, for now just press F5 or press the Start button on
the toolbar. Click one of your buttons. Does anything happen?
- To
make the buttons do something we need to attach event procedures to
them. These are instructions that controls execute when specific events
are fired. To attach an event procedure to each of our buttons we need to
open the Code Window and write some Visual Basic instructions. To open the
Code Window, double click on the blue button. You will be inside of the
Click() event procedure. Type in the following code so that your procedure
looks like this:
Private Sub cmdBlue_Click()
First.BackColor = vbBlue
End Sub
- While you are still in the Code Window
notice that there are two drop down boxes at the top. The one on the left
should say “cmdBlue”. This is the object list box. The one on the
right should say “Click”. This is the procedure list box. Select
“cmdRed” from the object list box and type in the following code so that
your procedure looks like this:
Private Sub cmdRed_Click()
First.BackColor = vbRed
End Sub
- Close
the Code Window and run your program. What happens?
- Let’s
add one more button to demonstrate some other properties you can
manipulate. Add a button control and change the caption and name
properties to “Name” and “cmdName”.
- Now
add a textbox control. This is added to the form the same way as the
button control. change the name property to “txtName” and the text
property to your name. If you’d like, you can also change the font
property to set the size, style, and face properties of the font.
- Open
up the Code Window by double-clicking on the form or by selecting “View”
and “Code” from the menu bar.
- Select
“Form” in the object list box and “Load” in the procedure list box. Type
in the following code:
Private Sub Form_Load()
txtName.Visible = False
End Sub
- Now
select “cmdName” and “Click” and type in the following code:
Private Sub cmdName_Click()
txtName.Visible = True
End Sub
- Run
your modified program. What happens when your form first loads? When you
click the Name button?
- Save
your work before closing VB and leaving the lab.
Additional reading and
examples:
For more information and exercises
on adding controls and event procedures, check out Chapters 5 and 7 of your VB
book.