Control design

A control is a visible element in a form or window, which displays data and/or supports specific functionality (actions). Controls are

• data controls (fields or lists)
• complex controls (sub forms)
• action elements (menu items, buttons and tool bars)
• constant elements (images, text, ...)

Data and complex controls may get inner and/or outer elements as caption, tool bars or buttons, but also other related data controls. Thus, an outer complex control might be defined for a list control in order to display data for the selected list entry.

Data controls are associated with a data source. The GUI framework cares about displaying data and refreshing data in a control, when it changes. Depending on the type of data source, ODABA controls may display elementary data fields, but also complex controls, lists and trees displaying complex data or collections.