类图如下:
定义代码如下:
/// <summary> /// 深拷贝接口 /// </summary> interface IDeepCopy { object DeepCopy(); } /// <summary> /// 浅拷贝接口 /// </summary> interface IShallowCopy { object ShallowCopy(); } /// <summary> /// 教室信息 /// </summary> class ClassRoom : IDeepCopy, IShallowCopy { public int RoomID = 1; public string RoomName = "Room1"; public override string ToString() { return "RoomID=" + RoomID + "\tRoomName=" + RoomName; } public object DeepCopy() { ClassRoom r = new ClassRoom(); r.RoomID = this.RoomID; r.RoomName = this.RoomName; return r; } public object ShallowCopy() { //直接使用内置的浅拷贝方法返回 return this.MemberwiseClone(); } } class Student : IDeepCopy, IShallowCopy { //为了简化,使用public 字段 public string Name; public int Age; //自定义类型,假设每个Student只拥有一个ClassRoom public ClassRoom Room = new ClassRoom(); public Student() { } public Student(string name, int age) { this.Name = name; this.Age = age; } public object DeepCopy() { Student s = new Student(); s.Name = this.Name; s.Age = this.Age; s.Room = (ClassRoom)this.Room.DeepCopy(); return s; } public object ShallowCopy() { return this.MemberwiseClone(); } public override string ToString() { return "Name:" + Name + "\tAge:" + Age + "\t" + Room.ToString(); } }pastingpasting 测试代码:
Student s1 = new Student("Vivi", 28); Console.WriteLine("s1=[" + s1 + "]"); Student s2 = (Student)s1.ShallowCopy(); //Student s2 = (Student)s1.DeepCopy(); Console.WriteLine("s2=[" + s2 + "]"); //此处s2和s1内容相同 Console.WriteLine("-----------------------------"); //修改s2的内容 s2.Name = "tianyue"; s2.Age = 25; s2.Room.RoomID = 2; s2.Room.RoomName = "Room2"; Console.WriteLine("s1=[" + s1 + "]"); Console.WriteLine("s2=[" + s2 + "]"); //再次打印两个对象以比较 Console.ReadLine();
运行结果:
a.ShallowCopy s1=[Name:Vivi Age:28 RoomID=1 RoomName=Room1] s2=[Name:Vivi Age:28 RoomID=1 RoomName=Room1] ------------------------------------------------------------- s1=[Name:Vivi Age:28 RoomID=2 RoomName=Room2] s2=[Name:tianyue Age:25 RoomID=2 RoomName=Room2] b.DeepCopy s1=[Name:Vivi Age:28 RoomID=1 RoomName=Room1] s2=[Name:Vivi Age:28 RoomID=1 RoomName=Room1] ----------------------------- s1=[Name:Vivi Age:28 RoomID=1 RoomName=Room1] s2=[Name:tianyue Age:25 RoomID=2 RoomName=Room2] 从以上结果可以看出,深拷贝时两个对象是完全“分离”的,改变其中一个,不会影响到另一个对象; 浅拷贝时两个对象并未完全“分离”,改变顶级对象的内容,不会对另一个对象产生影响,但改变子对象的内容,则两个对象同时被改变。 这种差异的产生,即是取决于拷贝子对象时复制内存还是复制指针。深拷贝为子对象重新分配了一段内存空间,并复制其中的内容; 浅拷贝仅仅将指针指向原来的子对象。 示意图如下: 2.浅拷贝与赋值操作 大多数面向对象语言中的赋值操作都是传递引用,即改变对象的指针地址,而并没有复制内存,也没有做任何复制操作。 由此可知,浅拷贝与赋值操作的区别是 顶级对象的复制与否。当然,也有一些例外情况,比如类型定义中重载赋值操作符(assignment operator), 或者某些类型约定按值传递,就像C#中的结构体和枚举类型。 赋值操作示意图如下: