Graphical User Interfaces

This chapter discusses graphical user interfaces (GUIs) that are an absolute must for new programs today. In contrast, older COBOL programs have mostly the conventional textual interface, because they have a terminal origin. The difference between the two types of user interfaces is that event-oriented programming requires not only more complex programming and the use of some classes but a totally different approach. A GUI is based on a different programming flow. This kind of interface is event-controlled—special program parts are executed for different user actions, such as pressing a key, selecting a menu item, or clicking the mouse on a control element. Creating a user interface and working with such an interface depends largely on the class library. The Object Inspector is the connection between application's visual appearance and the code that makes application run. The Object Inspector enables a user to set design-time properties for components placed on a form, create, and help navigate through event handlers, and filter visible properties and events.