如何使用，少用

ListOut:IList<out T>  
ListOut<int> lint=new ListOut<int>(){0,1,2};  
ListOut<Object> lobject=new ListOut<Object>();  
lobject=lint;  

 ListIn:IList<in T>  
ListIn<Object> lobject = new ListIn<Object>(){"0","1","2"};  
ListIn<int> lint=new ListIn<int>;  
lint = lobject;