对值类型装箱拆箱保持不变性，对引用类型不保持(保持相关性)

class Animal{     public string Name;}class Person{     public string Name;     public Animal animal;}static void Main(string[] args)        {                       Person p1;            p1.Name = "小明";            p1.animal = new Animal();            p1.animal.Name = "乌龟";            object o = p1;   //此时是将引用类型赋值给obj类型            p1.Name = "小红";            p1.animal.Name = "兔子";            Person p2 = (Person)o;//将obj类型强转为Person类型 此时上面付给animal 的Name 将 变成兔子            Console.WriteLine(p1.animal.Name);            Console.WriteLine(p2.animal.Name);            Console.ReadKey();}