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GUI for .NET Primer
Basic Types of Forms and Application Design : What is a form?

What is a form?

Your GUI for .NET application will require the use of one or more types of forms. A form is a representation of any window displayed in your application. ABL supports several types of forms for building different types of applications. The OpenEdge .NET Progress.Windows.Form class can be used to create standard, borderless, and floating windows. You can also use this class to create modal windows, such as a dialog. A special kind of form, the Multiple Document Interface (MDI) form, can contain other forms as child forms, including ABL windows that you might have created in OpenEdge version 11 or earlier.
The form types you choose to meet your application requirements determine the objects, controls, methods, and event handlers necessary to tie it all together.
In ABL a WINDOW widget is created using the CREATE WINDOW statement. In this example the variable custWin contains a handle to the newly created window:
A .NET form is similar to an ABL WINDOW widget. In ABL a .NET form is typically an instance of the Progress.Windows.Form class and is created using the NEW function. In this example, FormObjectRef contains an object reference to the new .NET form:
DEFINE VARIABLE FormObjectRef AS CLASS Progress.Windows.Form NO-UNDO.
FormObjectRef = NEW Progress.Windows.Form( ).
* Main form
* MDI and MDI child forms
* Multiple, non-modal forms
* Dialog forms
* Creating and initializing forms