请问没有OnMouseLeave事件的控件如何判断鼠标离开？(20分)

请问没有OnMouseLeave事件的控件如何判断鼠标离开？

Procedure OnMouseLeave( msg : TCMMouseLeave ); message cm_OnMouseLeave;

private
proocedure CMMouseLeave(var Msg: TMessage); message CM_MOUSELEAVE;

implementation
procedure TSomeForm.CMMouseLeave(var Msg: TMessage);
begin
{ anObject is the control which the mouse has just gone out of }
anObject := TObject(Msg.lParam);
if anObject nil then begin
{ First, you must find WHICH is the control }
{ the mouse cursor has just left, }
{ then, determine what action to do, etc... }
end;
end;

处理 CMMouseLeave！！

谢谢各位
我是初学者，积分少，问题又多，只好少给一点了，不好意思