Как писать Win32API приложения на Delphi

Code:

function WindowProc(wnd:HWND; Msg : Integer; Wparam:Wparam;

        Lparam: Lparam): Lresult; stdcall;

var

nCode, ctrlID, size: word;

pt: TPoint;

s: string;

begin

case msg of

wm_command:

begin

   nCode:=hiWord(wParam);

   ctrlID:=loWord(wParam);

   case ctrlID of

     IDHELP:

     begin

       DialogBox(hInstance,'#501',wnd,@DialogFunc);

     end;

     IDOK:

     begin

       DialogBoxParam(hInstance,'#503',wnd,@DialogFunc2, Integer(pd));

       s := 'Login: '+pd^.login;

       s := s + ' ' + 'Pass: '+pd^.pass;

       ListBox_AddString(lb, s);

     end;

     IDCANCEL:

     begin

       DestroyWindow(wnd);

     end;

   end;

end;

wm_destroy :

begin

   Dispose(pd);

   postquitmessage(0); exit;

   Result:=0;

end;

else

   Result := DefWindowProc(wnd, msg, wparam, lparam);

end;

end;