深复制和浅复制

深复制和浅复制的区别在于引用的复制，值类型系统会自动完成，而且完成的很好
using System;

public class IdInfo

{

    public int IdNumber = 2;



}



public class Person : ICloneable

{

    public int Age;

    public string Name;

    public IdInfo IdInfo;

    public Person()

    { IdInfo = new IdInfo(); }

    public Person ShallowCopy()//浅赋值也成为影子拷贝

    {

        return (Person)(MemberwiseClone());

    }



    public object Clone()//深复制

    {



        //Person other=new Person()等效的

        //return other;

        return new Person();

    }

}



public class Example

{

    public static void Main()

    {



        Person p1 = new Person();

        p1.Age = 11;

        p1.Name = "lei";

        Person p2 = p1.ShallowCopy();

        Person p3 = (Person)p1.Clone();

        Console.WriteLine("Original values of p1 and p2,p3:");

        Console.WriteLine("   p1 instance values: ");

        DisplayValues(p1);

        Console.WriteLine("   p2 instance values:");

        DisplayValues(p2);

        Console.WriteLine("   p3 instance values: ");

        DisplayValues(p3);

        Console.ReadLine();

    }



    public static void DisplayValues(Person p)

    {

        Console.WriteLine("      Name: {0:s}, Age: {1:d}", p.Name, p.Age);

        Console.WriteLine("      Value: {0:d}", p.IdInfo.IdNumber);

    }

}

为什么p3的值是空的，注意看clone这个深复制函数，它返回一个局部变量，而这个局部变量的值是未知的，输出的值是系统初始化的值，string型初始化为“”，int型初始化为0！

using System;

public class IdInfo

{

    public int IdNumber = 2;



}



public class Person : ICloneable

{

    public int Age;

    public string Name;

    public IdInfo IdInfo;

    public Person()

    { IdInfo = new IdInfo(); }

    public Person ShallowCopy()//浅赋值也成为影子拷贝

    {

        return (Person)(MemberwiseClone());

    }



    public object Clone()//深复制

    {

        Person other;

        other=(Person)this.MemberwiseClone();//语句1
        语句1执行完后，局部变量other的值类型成员有了自己的空间，但是引用类型成员IdInfo指向的是this所指的空间，也就是说other和this所指的变量共同指向同一个空间

        other.IdInfo = new IdInfo();//语句2  这句执行后other的引用类型的成员IdInfo有了属于自己的空间

        return other;

    }

}

 //语句1和语句2的顺序不能颠倒，不然会发生如下错误



public class Example

{

    public static void Main()

    {



        Person p1 = new Person();

        p1.Age = 11;

        p1.Name = "lei";

        Person p2 = p1.ShallowCopy();

        Person p3 = (Person)p1.Clone();

        Console.WriteLine("Original values of p1 and p2,p3:");

        Console.WriteLine("   p1 instance values: ");

        DisplayValues(p1);

        Console.WriteLine("   p2 instance values:");

        DisplayValues(p2);

        Console.WriteLine("   p3 instance values: ");

        DisplayValues(p3);

       // Change the value of p1 properties and display the values of p1 and p2,p3.

        p1.Age = 12; //p1改变观看p2,p3的变化;

        p1.Name = "cao"; 

        p1.IdInfo.IdNumber = 3;

        p3.IdInfo.IdNumber = 4;//p3的值改变

        Console.WriteLine("\nValues of p1 and p2 after changes to p1:");

        Console.WriteLine("   p1 instance values: ");

        DisplayValues(p1);

        Console.WriteLine("   p2 instance values:");

        DisplayValues(p2);

        Console.WriteLine("   p3 instance values: ");

        DisplayValues(p3);

        Console.ReadLine();

       }



    public static void DisplayValues(Person p)

    {

        Console.WriteLine("      Name: {0:s}, Age: {1:d}", p.Name, p.Age);

        Console.WriteLine("      Value: {0:d}", p.IdInfo.IdNumber);

    }

}

下面是msn中的：

using System;



public class IdInfo

{

    public int IdNumber;



    public IdInfo(int IdNumber)

    {

        this.IdNumber = IdNumber;

    }

}



public class Person 

{

    public int Age;

    public string Name;

    public IdInfo IdInfo;



    public Person ShallowCopy()

    {

       return (Person)this.MemberwiseClone();

    }



    public Person DeepCopy()

    {

       Person other = (Person) this.MemberwiseClone(); 

       other.IdInfo = new IdInfo(this.IdInfo.IdNumber);

       return other;

    }

}



public class Example

{

    public static void Main()

    {

        // Create an instance of Person and assign values to its fields.

        Person p1 = new Person();

        p1.Age = 42;

        p1.Name = "Sam";

        p1.IdInfo = new IdInfo(6565);



        // Perform a shallow copy of p1 and assign it to p2.

        Person p2 = (Person) p1.ShallowCopy();



        // Display values of p1, p2

        Console.WriteLine("Original values of p1 and p2:");

        Console.WriteLine("   p1 instance values: ");

        DisplayValues(p1);

        Console.WriteLine("   p2 instance values:");

        DisplayValues(p2);



        // Change the value of p1 properties and display the values of p1 and p2.

        p1.Age = 32;

        p1.Name = "Frank";

        p1.IdInfo.IdNumber = 7878;

        Console.WriteLine("\nValues of p1 and p2 after changes to p1:");

        Console.WriteLine("   p1 instance values: ");

        DisplayValues(p1);

        Console.WriteLine("   p2 instance values:");

        DisplayValues(p2);



        // Make a deep copy of p1 and assign it to p3.

        Person p3 = p1.DeepCopy();

        // Change the members of the p1 class to new values to show the deep copy.

        p1.Name = "George";

        p1.Age = 39;

        p1.IdInfo.IdNumber = 8641;

        Console.WriteLine("\nValues of p1 and p3 after changes to p1:");

        Console.WriteLine("   p1 instance values: ");

        DisplayValues(p1);

        Console.WriteLine("   p3 instance values:");

        DisplayValues(p3);

    }



    public static void DisplayValues(Person p)

    {

        Console.WriteLine("      Name: {0:s}, Age: {1:d}", p.Name, p.Age);

        Console.WriteLine("      Value: {0:d}", p.IdInfo.IdNumber);

    }

}
http://msdn.microsoft.com/zh-cn/library/system.object.memberwiseclone(v=vs.110).aspx

 

ICloneable 接口

支持克隆，即用与现有实例相同的值创建类的新实例。

public interface ICloneable

ICloneable 类型公开以下成员。

ICloneable.Clone 方法

创建作为当前实例副本的新对象。

Object Clone()

返回值

类型：System.Object

作为此实例副本的新对象。



Object.MemberwiseClone 方法

创建当前 Object 的浅表副本。

protected Object MemberwiseClone()

返回值

类型：System.Object

当前 Object 的浅表副