Vcl.ComCtrls.TCustomUpDown.OnChanging
Delphi
property OnChanging: TUDChangingEvent read FOnChanging write FOnChanging;
C++
__property TUDChangingEvent OnChanging = {read=FOnChanging, write=FOnChanging};
Properties
| Type | Visibility | Source | Unit | Parent |
|---|---|---|---|---|
| event | protected | Vcl.ComCtrls.pas Vcl.ComCtrls.hpp |
Vcl.ComCtrls | TCustomUpDown |
Description
Occurs when the position of an up-down control is about to change.
Write an OnChanging event handler (type: TUDChangingEvent) to conditionally disallow changes to the value of Position. Set the AllowChange parameter to false to prevent a change to the current value of Position.
OnChanging occurs both when the user clicks the arrow buttons of the up-down control and when an attempt is made to change the value of Position programmatically. To determine which button the user clicked, use the OnChangingEx event or the OnClick event, both of which follow the OnChanging event.