Release 10.1A: OpenEdge Getting Started:
OpenEdge Reference Architecture

View components

View components provide the primary interaction with an end-user. Typically, View components are represented by windows, dialog boxes, or HTML pages. Each View component also serves as a container of other components, such as buttons, text fields, drop-down lists, and so on.

By using View components in conjunction with Model and Controller components, you can create a more flexible Presentation Layer application structure. Keeping View component functionality focused on user interaction (leaving other client-side processing to non-interface components) allows for the reuse of application logic between multiple View components.

View components should require a minimal amount of application code to be associated with them. Instead, actions that require additional processing should rely on either Model or Controller components. View components should only be responsible for the interaction of an application in conjunction with a user.

Properties of View components

Typical View components have a large number of properties associated with them. Most of these properties, however, are associated with the layout of the component and are used at the time that a user interface is designed by a developer.

It is possible to design a View component with additional properties to store unique instance information. You could, for example, create properties to hold a specific instance ID for a View component, allowing multiple instances of a window to be easily referenced at run time.

Routines of View components

The most common routines of a View component directly relate to user interface events that require additional processing or actions. The pressing of a button by a user, for example, might require actions other than the default behavior (the button visually showing the selection action) to occur.

It is also possible to define additional routines for a View component. This might be useful when many user interface events require a similar action to take place. Rather than repeating the same user interface logic in multiple locations, the event routines all call a common routine.