The Appearance of Forms
The main characteristic of a Form is the title bar on which the Form's caption
is displayed. On the left end of the title bar is the Control Menu icon. Clicking
this icon opens the Control Menu. Maximize, Minimize and Close buttons can be
found on the right side of the Form. Clicking on these buttons performs the associated
function.
The following figure illustrates the appearance of a Form
The control menu contains the following commands :
-
Restore : Restores a maximized Form to the size it was before it was
maximized; available only if the Form has been maximized.
-
Move : Lets the user moves the Form around with the mouse
-
Size : Lets the user resizes the control with the mouse
-
Minimize: Minimizes the Form
-
Maximize : Maximizes the Form
-
Close : Closes the Form
Setting the Start-Up Form
A typical application has more than a single Form. When an application runs
the main Form is loaded. By setting the Project properties you can control which
Form is to be displayed in the Start-Up of the application. Following figure illustrates
the Project property window.
By default, Visual Basic suggests the name of the first Form created when the
project started.
Loading and Unloading Forms
In order to load and unload the forms, Load and Unload statements are used.
The Load statement has the following syntax :
Load FormName
And the Unload statement has the following syntax :
Unload FormName
The FormName variable is the name of the Form to be loaded or unloaded. Unlike
the Show method which cares of both loading and displaying the Form, the load
statement doesn't show the Form. You have to call the Form's Show method to display
it on the desktop.
Showing and Hiding Forms
Show method is used to Show a Form. If the Form is loaded but invisible, the
Show method is used to bring the Form on Top every other window. If the Form is
not loaded, the Show method loads it and then displays it.
Syntax of the Show method of the Form
FormName.Show mode
The FormName variable is the Form's name, and the optional argument
mode determines whether the Form will be Modal or not. It can have one of the
following syntax :
* 0-Modeless (default)
* 1-Modal
Modeless Forms are the normal Forms. Modeless Forms interact with the user
and the user allowed to switch to any other Form of the application. If you do
not specify the optional mode argument, by default the mode is set to modeless.
The Modal Forms takes the total control of the application where user cannot
switch to any other Forms in the application unless the Form is closed. A modal
Form, thus, must have a Close button or some means to close the Form in order
to return to the Form where the Modal Form was loaded.
Hiding Forms
The Hide method is used to hide a Form. The following is the syntax of the
Hide Method.
FormName.Hide
To hide a Form from within its own code, the following code can be used.
Me.Hide
You must understand that the Forms that are hidden are not unloaded ; they
remains in the memory and can be displayed instantly with the Show Method. When
a Form is hidden, you can still access its properties and code. For instance,
you can change the settings of its Control Properties or call any Public functions
in the Form.
The following is an example illustrates the Show method and Mode statement
* Open a new Project and save the Project
Design the application as shown below
| Object |
Property |
Setting |
| Form |
Caption
Name |
Form1
frm1 |
| Form |
Caption
Name |
Form2
frm2 |
| Form |
Caption
Name |
Form3
frm3 |
| Label |
Caption
Name |
Click on a button to display a Form
Label1 |
The following code is typed in the Click event of the command buttons
Run the application. Clicking on the buttons will display the Forms respectively.
But you can see that in the cmd2_Click( ) event additionally VbModal argument
has been added. You can see the difference after you display the forms by clicking
on the command buttons. You can notice that you cannot switch to any other Forms
in the application unless you close the Form3. (Download
the source code)
Finding out the difference between Unload and Hide method
To know what the difference is between Unload and Hide methods we will do an
example. Open a new project and save the project. Draw two buttons on the form
and name those as shown above.
In the click event of the Hide button Following code is entered.
Me.Hide
In the click event of the Unload button following code is entered.
Unload Me
Save the project and run the application. Once you click on Hide button you
can note that the Form is invisible but the application is still running. But
when you click on Unload button you can see that the application is terminated.
