OnNavigate event

Applies To
TQDB, TQDBItem, TQDBView

Declaration
property OnNavigate : TNotifyEvent;

Description
Whenever the index pointer is successfully moved the OnNavigate event is triggered. Changing the ItemIndex property directly or via FirstItem, LastItem, NextItem or PrevItem triggers OnNavigate, as do Add and Delete and the searching methods CloseMatch, ExactMatch, PartialMatch, and PatternMatch. The Items and ItemsByKey array properties may also trigger this event.

If, however, the above methods are sandwiched in a BeginUpdate - EndUpdate block OnNavigate is not triggered. This can speed up repeated operations by cutting out the screen updating that usually happens in the OnNavigate event.

N.B.: This event is only triggered if the ItemIndex property actually changes. The BoF and EoF properties, which are set when ItemIndex does not change, should never be tested in OnNavigate event handlers.