unit UpDown1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  ComCtrls;

type
  TUpDown1 = class(TUpDown)
  private
    PMouseEnter:TNotifyEvent;
    PMouseLeave:TNotifyEvent;
    procedure MouseEnterProc(var msg:TMessage);message CM_MOUSEENTER;
    procedure MouseLeaveProc(var msg:TMessage);message CM_MOUSELEAVE;
  protected
    { Protected declarations }
  public
    { Public declarations }
  published
    property OnMouseEnter:TNotifyEvent Read PMouseEnter Write PMouseEnter;
    property OnMouseLeave:TNotifyEvent Read PMouseLeave Write PMouseLeave;
  end;

procedure Register;

implementation

procedure Register;
begin
  RegisterComponents('Samples', [TUpDown1]);
end;
procedure TUpDown1.MouseEnterProc (var msg:TMessage);
begin
  if Assigned(PMouseEnter) then PMouseEnter(Self);
end;
procedure TUpDown1.MouseLeaveProc (var msg:TMessage);
begin
  if Assigned(PMouseLeave) then PMouseLeave(Self);
end;

end.