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Programming Widgets

Before you work with each individual widget, it’s important to understand the programming concepts and structures that support your ability to define and modify the characteristics of a widget. Table 7–1 organizes these concepts and structures around the life span of a widget.

Table 7–1: Ways to Define or Modify a Data Widget 
Stage
Description
Widget definition
For variables, the DEFINE VARIABLE statement supports the VIEW-AS phrase. This phrase enables you to specify a widget type and define its major characteristics.
For fields, the Data Dictionary supports properties that match all the options of the DEFINE VARIABLE statement.
Container definition
When you define your frames and dialog boxes, you specify the widgets found in the containers. After each widget reference, there are several 4GL options you can specify to further define the characteristics of the widget. Collectively, these options are referred to as the format phrase.
The DEFINE FRAME statement supports the frame phrase, which you use to define the characteristics of the frame widget. Some frame phrase options modify the characteristics of the widgets contained in the frame.
Before display
Progress screen input and output statements, like DISPLAY, support both the format phrase and the frame phrase. You can override earlier format and frame phrase options by respecifying them on a screen I/O statement.
Note that some control blocks also support the frame phrase.
After display
After a widget appears on screen, you can no longer modify many characteristics with 4GL statements. Instead, you must access the corresponding widget attributes directly. The Progress Language Reference contains an appendix that details which attributes you can set in this way.


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