arcengine实现右键菜单打开/关闭所有图层

参考资料:  http://developer.51cto.com/art/201104/256774.htm

参照后自己做的:

关于右键菜单的几个有价值的网址：

http://blog.****.net/my_lord_/article/details/52787300

http://www.cnblogs.com/hans_gis/archive/2011/04/21/2023366.html

http://www.gissky.net/Item/1544.aspx

https://www.cnblogs.com/xiuchuan/p/6850423.html

https://www.cnblogs.com/fengzhiwei-blog/p/4934495.html

https://max.book118.com/html/2016/1226/77234014.shtm