事件，委托，action与func文章不错的

https://www.cnblogs.com/yinqixin/p/5056307.html

https://www.cnblogs.com/BLoodMaster/archive/2010/07/06/1771926.html

 

https://www.cnblogs.com/772933011qq/p/6369381.html

 

http://www.cnblogs.com/wudiwushen/archive/2010/02/11/1667588.html