C#浅拷贝和深拷贝实例剖析【C#.Net教程】,C# 浅拷贝 深拷贝

在有些时刻，我们需要从数据库读取数据添补对象或从硬盘读取文件添补对象，然则如许做相对耗时。这时刻我们就想到了对象的拷贝。本文即以实例情势剖析了C#浅拷贝和深拷贝的用法。详细以下：

一、浅拷贝

1.什么是"浅拷贝"：

当针对一个对象前拷贝的时刻，关于对象的值范例成员，会复制其自身，关于对象的援用范例成员，仅仅复制对象援用，这个援用指向托管堆上的对象实例。

2.有一个对象，包括援用范例的类成员和值范例的struct成员

Cinema包括援用范例成员Room和值范例成员Film。

public class Room
{
  public int _maxSeat;
 
  public Room(int maxSeat)
  {
    this._maxSeat = maxSeat;
  }
}
 
public struct Film
{
  public string _name;
 
  public Film(string name)
  {
    this._name = name;
  }
}
 
public class Cinema
{
  public Room _room;
  public Film _film;
 
  public Cinema(Room room, Film film)
  {
    this._room = room;
    this._film = film;
  }
 
  public object Clone()
  {
    return MemberwiseClone(); //对援用范例实行浅复制
  }
}

3.测试拷贝后的效果

①打印出本来对象拷贝前值范例和援用范例成员的值
②对本来对象拷贝，打印出复制对象值范例和援用范例成员的值
③转变本来对象的值，再次打印本来对象的值范例和援用范例成员的值
④再次打印复制对象值范例和援用范例成员的值

static void Main(string[] args)
{
  Room room1 = new Room(60);
  Film film1 = new Film("故里防地");
  Cinema cinema1 = new Cinema(room1, film1);
  Cinema cinema2 = (Cinema)cinema1.Clone();
  Console.WriteLine("拷贝之前，构形成员的字段值为{0}，援用范例成员的字段值为{1}", cinema1._film._name,cinema1._room._maxSeat);
 
  Console.WriteLine("拷贝以后，新的构形成员的字段值为{0}，援用范例成员的字段值为{1}", cinema2._film._name, cinema2._room._maxSeat);
 
  //修正拷贝之前援用范例的字段值
  cinema1._film._name = "极品飞车";
  cinema1._room._maxSeat = 80;
 
  Console.WriteLine("修正以后，构形成员的字段值为{0}，援用范例成员的字段值为{1}", cinema1._film._name, cinema1._room._maxSeat);
  Console.WriteLine("修正以后，新的构形成员的字段值为{0}，援用范例成员的字段值为{1}", cinema2._film._name, cinema2._room._maxSeat);
 
  Console.ReadKey();
}

剖析：

浅拷贝症结点是对援用范例拷贝的是对象援用，这个援用指向托管堆上的对象实例。转变原对应援用范例的值，会影响到复制对象。

二、深拷贝

1.什么是"深拷贝"

对援用成员指向的对象也举行复制，在托管堆上赋值本来对象实例所包括的数据，再在托管堆上建立新的对象实例。

2.经由过程对每一个对象成员举行复制举行深拷贝

public object Clone()
{
  Room room = new Room();
  room._maxSeat = this._room._maxSeat;//复制当前援用范例成员的值到新对象
  Film film = this._film; //值范例直接赋值
  Cinema cinema = new Cinema(room, film);
  return cinema;
}

3.也能够经由过程序列化和反序列化举行深拷贝

public object Clone1()
{
  BinaryFormatter bf = new BinaryFormatter();
  MemoryStream ms = new MemoryStream();
  bf.Serialize(ms, this); //复制到流中
  ms.Position = 0;
  return (bf.Deserialize(ms));
}

4.采纳序列化和反序列化深拷贝，但必需把一切的类打上[Serializable]，测试代码以下：

[Serializable]
public class Room
{
  public int _maxSeat;
 
  public Room()
  {}
 
  public Room(int maxSeat)
  {
    this._maxSeat = maxSeat;
  }
}
 
[Serializable]
public struct Film
{
  public string _name;
 
  public Film(string name)
  {
    this._name = name;
  }
}
 
[Serializable]
public class Cinema
{
  public Room _room;
  public Film _film;
 
  public Cinema(Room room, Film film)
  {
    this._room = room;
    this._film = film;
  }
 
  //浅拷贝
  //public object Clone()
  //{
  //  return MemberwiseClone(); //对援用范例实行浅复制
  //}
 
  //深拷贝 对每一个对象成员举行复制
  public object Clone()
  {
    Room room = new Room();
    room._maxSeat = this._room._maxSeat;//复制当前援用范例成员的值到新对象
    Film film = this._film; //值范例直接赋值
    Cinema cinema = new Cinema(room, film);
    return cinema;
  }
 
  //运用序列化和反序列化举行复制
  public object Clone1()
  {
    BinaryFormatter bf = new BinaryFormatter();
    MemoryStream ms = new MemoryStream();
    bf.Serialize(ms, this); //复制到流中
    ms.Position = 0;
    return (bf.Deserialize(ms));
  }
}

5.测试拷贝后的效果

static void Main(string[] args)
   {
     Room room1 = new Room(60);
     Film film1 = new Film("故里防地");
     Cinema cinema1 = new Cinema(room1, film1);
     Cinema cinema2 = (Cinema)cinema1.Clone1();
     Console.WriteLine("拷贝之前，构形成员的字段值为{0}，援用范例成员的字段值为{1}", cinema1._film._name,cinema1._room._maxSeat);
 
     Console.WriteLine("拷贝以后，新的构形成员的字段值为{0}，援用范例成员的字段值为{1}", cinema2._film._name, cinema2._room._maxSeat);
 
     //修正拷贝之前援用范例的字段值
     cinema1._film._name = "极品飞车";
     cinema1._room._maxSeat = 80;
 
     Console.WriteLine("修正以后，构形成员的字段值为{0}，援用范例成员的字段值为{1}", cinema1._film._name, cinema1._room._maxSeat);
     Console.WriteLine("修正以后，新的构形成员的字段值为{0}，援用范例成员的字段值为{1}", cinema2._film._name, cinema2._room._maxSeat);
 
     Console.ReadKey();
   }

效果：