u 写代码如下，然后保存该单元为mypanelunit。
unit mypanelunit;
interface
uses classes, extctrls, messages, controls;
type
tmouseactionevent = procedure(sender: tobject) of object;
tmypanel = class(tpanel)
private
fonmouseenter, fonmouseleave:
fouseactionevent;
//截获鼠标进入消息
procedure wmmouseenter (var message:
tmessage); message cm_mouseenter;
//截获鼠标移开消息
procedure wmmouseleave (var message:
tmessage); message cm_mouseleave;
published
property onmouseenter: tmouseactionevent read
