MenuItemKeepIdx.Checked = Not MenuItemKeepIdx.Checked这句如何理解

MenuItemKeepIdx.Checked = Not MenuItemKeepIdx.Checked这句怎么理解?
MenuItemKeepIdx.Checked   =   Not   MenuItemKeepIdx.Checked这句怎么理解?

------解决方案--------------------
给分 取反的意思! 如果是True 就变成false 如果是false 就变成true