Unit 'Controls' Package
[Overview][Constants][Types][Classes][Procedures and functions][Variables][Index] [#lcl]


Event handler signalled for a leftward movement of the mouse wheel.


Source position: controls.pp line 1573

protected property TControl.OnMouseWheelLeft : TMouseWheelUpDownEvent
  read FOnMouseWheelLeft
  write FOnMouseWheelLeft;


OnMouseWheelLeft is a TMouseWheelUpDownEvent property with the event handler signalled when the mouse wheel is "tilted" towards the left. It is signalled (when assigned) from the DoMouseWheelLeft method, and occurs when the LM_MOUSEHWHEEL message is handled in the WMMouseHWheel method.

Applications can implement and assign a TMouseWheelUpDownEvent to perform actions needed when the event has occurred in the control. The arguments to the event handler include:

The control for the event notification.
The shift modifier in effect when the event occurred.
The coordinates for the mouse pointer when the event occurred.
A variable argument which indicates if the wheel event is handled in the routine.

There are several horizontal mouse wheel event handlers, and they are signalled in order until a handler is found that responds to the event notification. These include:

OnMouseWheelLeft, and the other horizontal mouse wheel event handlers, require a mouse with a tilting scroll wheel to generate the event notification.

See also



Event handler signalled for a rightward movement of the mouse wheel.



Event handler signalled for a horizontal movement of the mouse wheel.



Event handler for mouse wheel turned.



Type of OnMouseWheelUp/Down event handlers.

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