MFC中不同窗口间的切换
https://blog.csdn.net/dpsying/article/details/17458401
http://www.docin.com/p-707972220.html
http://www.cnblogs.com/rrll/archive/2011/07/25/2115946.html
https://blog.csdn.net/lwqbrell/article/details/53966151
https://bbs.csdn.net/topics/390219947