类似的还有其他三个属性ChatEnabled、UserInfoEnabled、GroupMebEnabled，我通过控制MainState来控制界面UserControl的显隐： 之前我也是这样做的，不过控制的是普通界面元素的显隐（如Button，Textbook等），但是我发现同样的方法用在UserControl上就不管用了（结果是全部显示）。

This worked OK in the beginning. As my application grew, I wanted to take advantage of IoC in my ViewModel; there were repositories to inject as well as other dependencies. Because of these and other ...