同一个消息，俩种不同的方式//有什么区别，何时会被调用呢?
ON_MESSAGE(BN_CLICKED, OnClicked)
ON_BN_CLICKED(IDC_BUTTON1, &CPage::OnBnClickedButton1)
[解决办法]
ON_BN_CLICKED
The parent window of the button receives this notification code through the WM_COMMAND message
按钮的父窗口通过wm_command接受通知处理消息
ON_MESSAGE
Indicates which function will handle a user-defined message.
处理用户定义消息
