Progress
Language Tutorial
for Windows
Dynamic Widgets and Direct Manipulation
Two advanced topics that the tutorial did not go into are dynamic widgets and direct manipulation. Both of these concepts are covered in the Progress Programming Handbook .
All of the widget syntax you learned about in the tutorial produces static widgets. A static widget is one that is defined before use. Static syntax always includes the keyword DEFINE. Static widgets are most frequently used because Progress handles most of the work of displaying and updating these widgets. However, you may have a programming situation where you cannot predict the number of widgets you may need. Then you can use the dynamic syntax of a widget, which includes the keyword CREATE, to create the widgets at run time. Dynamic widgets require more explicit maintenance than static widgets.
Another advanced use of widgets available in graphical environments is to allow users to directly change physical attributes of widgets. For example, you may want to let your users rearrange the positions of buttons on a particular interface. Implementing direct manipulation involves working with widget attributes and special events that you have not yet learned about. The Progress Programming Handbook is your first step in learning about direct manipulation.
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