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property OnChanging: TNotifyEvent read FOnChanging write FOnChanging;


__property TNotifyEvent OnChanging = {read=FOnChanging, write=FOnChanging};


Type Visibility Source Unit Parent
event public
System.Classes TStringList


Occurs immediately before the list of strings changes.

Write an OnChanging event handler to prepare for changes in the list of strings. For example, if the string list is associated with a control, the OnChanging event handler could tell the control to disable repaints until the OnChange event is triggered, notifying the control that the list has finished changing.

Whenever strings in the list are added, deleted, moved, or modified, the following events take place:

  1. An OnChanging event occurs.
  2. The strings are added, deleted, moved, or modified.
  3. An OnChange event occurs after the changes are complete.

Note: OnChanging occurs for every change made to the list, regardless of whether the application calls BeginUpdate and EndUpdate around a series of changes.

OnChanging is an event handler of type TNotifyEvent.

See Also