Chapter 26: Using Controls

Overview

Controls are manipulable, self-contained screen objects that allow communication between users and software. Controls, widgets, gadgets, or gizmos — whatever you choose to call them — are primary building blocks for creating graphical user interfaces. They are closely identified with GUI development, being as fundamental to GUI construction as windows, menus, and dialog boxes.

When examined in light of users' goals, controls come in four basic flavors: imperative controls, used to initiate a function; selection controls, used to select options or data; entry controls, used to enter data; and display controls, used to directly manipulate the program visually. Some controls combine one or more of these flavors.

Most of the controls that we are familiar with are those that come standard with Windows, the Mac OS, and other common windowing interfaces. This set of canned controls has always been very limited in scope and power.