RAD Studio
How Actions Find Their Targets

What happens when an action fires describes the execution cycle that occurs when a user invokes an action. If no event handler is assigned to respond to the action, either at the action list, application, or action level, then the application tries to identify a target object to which the action can apply itself. 

The application looks for the target using the following sequence:

  1. Active control: The application looks first for an active control as a potential target.
  2. Active form: If the application does not find an active control or if the active control can't act as a target, it looks at the screen's ActiveForm.
  3. Controls on the form: If the active form is not an appropriate target, the application looks at the other controls on the active form for a target.
If no target is located, nothing happens when the event is fired. 

Some controls can expand the search to defer the target to an associated component; for example, data-aware controls defer to the associated dataset component. Also, some predefined actions do not use a target; for example, the File Open dialog.

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