4D Doc Center : What are active objects?

4D v13.4

What are active objects?

An active object is anything on a form that performs a database task or an interface function. There are many kinds of active objects. Fields are considered active objects. Other active objects — enterable objects (variables), combo boxes, drop-down lists, picture buttons, and so on — store data temporarily in memory or perform some action such as opening a dialog box, printing a report, or starting a background process.

In some cases, you can specify the active object’s action by making selections in the Property List window. For example, you can use built-in automatic button actions to specify the action of a button. In other cases, you specify the object’s action by writing a method that is automatically attached to the object.

You can use the following active objects in 4D:

Field and variable objects,
Buttons,
3D Buttons, 3D Check Boxes and 3D Radio Buttons,
Picture Buttons,
Button Grids,
Check Boxes,
Radio Buttons and Picture Radio Buttons,
Pop-up Menus/Drop-down Lists,
Combo Boxes,
Hierarchical Pop-up Menus and Hierarchical Lists,
Picture Pop-up Menus,
Indicators,
Tab Controls,
Splitters,
Web areas,
Plug-in areas,
List boxes (described in a separate chapter),
Subforms and widgets (described in a separate chapter).

A set of properties manages the appearance of active objects and how they work. There are specific properties covered in the descriptions for each type of objects as well as basic generic properties such as data entry control or display formats that are described in Properties for active objects.