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


Handles a KeyDown event before the widget processes the key.


Source position: controls.pp line 2194

protected function TWinControl.DoKeyDownBeforeInterface(

  var Message: TLMKey;

  IsRecurseCall: Boolean





Message examined in the method.

Function result

Set to True when the key was handled.


Key event handlers are invoked in sequence, until a handler is located which responds to the key.

First, all application wide handlers are invoked (TApplication.NotifyKeyDownBeforeHandler).

Second, the form handler is invoked when KeyPreview is requested.

Third, the DragManager is used to determine the dragging status for the control. It interprets the ESC key as a cancel dragging request, and the CTRL key as a request to ignore drag targets.

Finally, the TWinControl.OnKeyDown user handler is invoked.

If none of the handlers accept / respond to the key, the widgetset class is used to process the key.

See also



Handler for keyboard key pressed.



Notifies all ahtKeyDownBefore handlers.

CT Web help

CodeTyphon Studio