Introducing MDI ApplicationsMany of the applications that you create in Visual Basic consist of a series of independent forms. Each of these forms is displayed separately on the screen and is moved, maximized, or minimized separately from any other form. With this type of interface, you cannot easily organize the forms or deal with them as a group. Even with this limitation, this interface is a good one to use for many programs and is probably the most prevalent interface design. An alternative to this standard interface is the Multiple-Document Interface, or MDI. This type of application has one parent form that contains most of the other forms in the program. Other forms can be child forms, which are contained within the parent, or standard forms, which are not. With an MDI application, you can easily organize all the child forms or minimize the entire group of forms just by minimizing the parent form. Programs such as Microsoft Word and Excel are examples of MDI applications. If you have worked with these programs, you know that you can open multiple windows in the program, access them easily from the menu, and minimize the whole thing with a single click of the mouse. In version 5, even Visual Basic went to a true MDI interface style. Characteristics of MDI Parent FormsThe MDI form, also known as the parent form, is the container for all the child forms of the application. The MDI form has a number of characteristics that define its behavior. They are as follow:
Characteristics of MDI Child FormsJust as the MDI form has characteristics of its behavior, the MDI child forms also behave in a certain way. The characteristics of an MDI child form are as follow:
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