Delphi中的DBGrid如何实现使用鼠标滚轮上下滚动

procedure TForm1.ApplicationEvents1Message(var Msg: tagMSG;
var Handled: Boolean);
begin
if  (DBGrid1.Focused)  And  (Msg.message  =  WM_MOUSEWHEEL)  then
begin
if  Msg.wParam  >  0  then
SendMessage(DBGrid1.Handle,  WM_KEYDOWN,  VK_UP,  0)
else
SendMessage(DBGrid1.Handle,  WM_KEYDOWN,  VK_DOWN,  0);
Handled  :=  True;
end;
end;