Putting Theory into Practice

Using objects in an interface design does not guarantee usability. But applying object-based concepts does offer greater potential for a well-designed interface. As with any good user interface design, a good user-centered design process ensures the success and quality of the interface.

The first step to object-based design should begin as any good design with a thorough understanding of what users' objectives and tasks are. When doing the task analysis, identify the basic components or objects used in those tasks and the behavior and the characteristics that differentiate each kind of object, including the relationships of the objects to each other and to the user. Also identify the actions that are performed, the objects to which they apply, and the state information or attributes that each object in the task must preserve, display, and allow to be edited.

Once the analysis is complete, you can start identifying the user interfaces for the objects. Define how the objects you identified are to be presented, either as icons or data elements in a form. Use icons primarily for representing composite or container objects that need to be opened into their own windows. Attribute or state information should typically be presented as properties of the associated object, most often using property sheets. Map behaviors and operations to specific kinds of interaction, such as menu commands, direct manipulation, or both. Make these accessible when the object is selected by the user. The information in this guide will help you define how to apply the interfaces provided by the system.

Redesigning an existing Windows 3.1-based application to a more data-centered interface need not require an immediate, complete overhaul. You can begin the evolution by adding contextual interfaces such as pop-up menus, property sheets, and OLE drag and drop and by following the recommendations for designing your window title bars and icons.