TCanvas.OnChanging Event

Occurs just before a change is made to the image.

Pascal

property OnChanging: TNotifyEvent;

C++

__property TNotifyEvent OnChanging;

Description

Write an OnChanging event handler to take specific action before the image on the canvas changes. When an application calls one of the drawing methods of TCanvas, the following steps occur.

1An OnChanging event occurs.

2The TCanvas method makes a change to the image.

3An OnChange event occurs.