Vcl.Graphics.TCustomCanvas.OnChanging

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Delphi

property OnChanging: TNotifyEvent read FOnChanging write FOnChanging;

C++

__property System::Classes::TNotifyEvent OnChanging = {read=FOnChanging, write=FOnChanging};

Properties

Type	Visibility	Source	Unit	Parent
event	public	Vcl.Graphics.pas Vcl.Graphics.hpp	Vcl.Graphics	TCustomCanvas

Description

Occurs just before a change is made to the image.

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

1. An OnChanging event occurs.
2. The TCustomCanvas method makes the change to the canvas.
3. An OnChange event occurs.

See Also

• OnChange