说明：  本篇将和各位一起定义一个XP风格的CXPButton按钮类，目的不在于介绍CXPButton类的使用技巧，而在于向各位阐述实现 自绘按钮的方法。
(This with you to define an XP style CXPButton button class, the purpose is to introduce the use of CXPButton class skills, but rather explained to you and to achieve self-drawn button.)