c# 引用类型对象的深拷贝

时间:2022-12-08 19:54:03

c#中的对象大体分为值类型和引用类型,值类型大致包括 int, struct等,引用类型大致包括 自定义Class,object 等。string属于特殊的引用类型,不在本文的讨论之内。

值类型直接存储对象,而引用类型存储对象的地址,在对引用类型进行复制的时候,也只是复制对象的地址。

完全复制一个引用类型对象主要有几种方法:

1.添加一个Copy函数,进行拷贝(如果字段为引用类型,需要循环添加Copy函数,这样情况会变的十分复杂。)

namespace ConsoleApplication1
{
    class User
    {
        public string Name { get; set; }
        public string Sex { get; set; }
        public House Home { get; set; }
        public User Copy()
        {
            User newUser = (User)this.MemberwiseClone();
            newUser.Home = this.Home.Copy();
            return newUser;
        }
    }
    class House
    {
        public string Address { get; set; }
        public House Copy()
        {
            return (House)this.MemberwiseClone();
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            User a = new User();
            a.Name = "A";
            a.Home = new House() { Address = "长江路" };
            User b = a.Copy();
            b.Name = "B";
            b.Home.Address = "黄河路";
            Console.WriteLine(a.Name);
            Console.WriteLine(a.Home.Address);
            Console.ReadLine();
        }
    }
}

 

2.利用序列化反序列化(对性能会有杀伤)

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.Serialization.Formatters.Binary;
using System.Text;
using System.Threading.Tasks;

namespace Test
{
    class Program
    {
        static void Main(string[] args)
        {
            Test t1 = new Test();
            Console.WriteLine(t1.list.Count);
            Test t2 = (Test)Clone(t1);
            t2.list.Add("");
            Console.WriteLine(t2.list.Count);
            Console.WriteLine(t1.list.Count);
            Console.ReadLine();
        }

        public static object Clone(object obj)
        {
            BinaryFormatter bf = new BinaryFormatter();
            MemoryStream ms = new MemoryStream();
            bf.Serialize(ms, obj);
            ms.Position = 0;
            return (bf.Deserialize(ms)); ;
        }
    }

    [Serializable]
    public class Test
    {
        public List<string> list = new List<string>();
    }
}

3.利用反射(测试了一个网上的接口可用,但是对性能杀伤和序列化反序列化相当,而且可能对代码混淆有一定影响。   https://www.cnblogs.com/zhili/p/DeepCopy.html)

最后附上微软文档:

https://docs.microsoft.com/zh-cn/dotnet/api/system.object.memberwiseclone?redirectedfrom=MSDN&view=netframework-4.7.2#System_Object_MemberwiseClone