Learning message (6): You can also directly overwrite the wndproc or dispatch methods of the ancestor class to respond to messages.

Coverage: wndproc

Unit unit1; interfaceuses windows, messages, sysutils, variants, classes, graphics, controls, forms, dialogs; Type tform1 = Class (tform) protected procedure wndproc (VAR message: tmessage ); override; end; var form1: tform1; implementation {$ R *. DFM} procedure tform1.wndproc (VAR message: tmessage); begin inherited; If message. MSG = wm_lbuttondown then showmessage ('wndproc'); end.

 

Overwrite: Dispatch

Unit unit1; interfaceuses windows, messages, sysutils, variants, classes, graphics, controls, forms, dialogs; Type tform1 = Class (tform) public procedure dispatch (VAR message); override; end; var form1: tform1; implementation {$ R *. DFM} procedure tform1.dispatch (VAR message); begin inherited; If tmessage (Message ). MSG = wm_lbuttondown then showmessage ('dispatch '); end.