1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:
21:
22:
23:
24:
25:
26:
27:
28:
29:

const 
  WM_EditFree=WM_USER+1; 

type 
  TMyEdit=class(TEdit)
  private 
    procedure EditKeyPress(Sender: TObject); 
    procedure EditMsgHandler(var Msg: TMessage ); message WM_EditFree;
  public
    constructor Create(aOwner: TComponent);
  end; 

constructor TMyEdit.Create(aOwner: TComponent); 
begin 
  inherited Create(aOwner);
  OnKeyPress:=EditKeyPress;
  {...}
end; 

procedure TMyEdit.EditKeyPress(Sender: TObject); 
begin 
  {...} 
  PostMessage(self.Handle,WM_EditFree,0,0); 
end; 

procedure TMyEdit.EditMsgHandler(var Msg: TMessage); 
begin 
  self.Free; 
end;