Event Actions

Event actions are special blocks of logic in a procedure action diagram (PrAD) that can execute separately from the main body of PrAD logic. An event action is an extension of a procedure step because it shares views with the procedure step. The main use of an event action is for the user interface functionality and is typically tied to the presentation. Action blocks, in comparison, are pieces of code that typically perform actions against the database and are not tied to the presentation. The executing application queues all events. Event actions are executed in sequence, never in parallel.

Event actions are reusable and can be associated with many different events within the same procedure step. In such a situation, the event action would typically have a CASE OF COMMAND structure. The commands in the CASE OF COMMAND structure would be associated with different events.

In the Navigation Diagram tool, you add event actions from the Events pop-up. The field Action Name on that pop-up specifies the name for the event action.

Event actions can be associated with windows, dialogs, and controls. The event action logic executes depending on the action taken with the window, dialog, or control. The action is a combination of what the user does and what the application does. For example, a user clicks a control. The click event sets an exit state that causes a flow which closes the window. The user did not directly close the window. But as a result of the click event by the user, the application logic closed the window.