C#之相等性判斷探秘

　　C#實(shí)現(xiàn)相等性判斷的方法：

1. public virtual bool Equals(object obj);
2. public static bool Equals(object objA, object objB);
3. public static bool ReferenceEquals(object objA, object objB);
4. “==”運(yùn)算符

//確定指定的 System.Object 是否等于當(dāng)前的 System.Objectpublic virtual bool Equals(object obj){    return RuntimeHelpers.Equals(this, obj);}//確定是否將指定的 System.Object 實(shí)例視為相等public static bool Equals(object objA, object objB){    return ((objA == objB) || (((objA != null) && (objB != null)) && objA.Equals(objB)));}//確定指定的 System.Object 實(shí)例是否是相同的實(shí)例public static bool ReferenceEquals(object objA, object objB){    return (objA == objB);}==和 !=運(yùn)算符比較內(nèi)容

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using System;using System.Collections;using System.Collections.Generic;using System.Linq;using System.Text;namespace ValueTypeDemo{    //鞋子類    class Shoes    {        PRivate string name; //品名        private int price;  //單價        public string Name        {            get { return name; }            set { name = value; }        }        public int Price        {            get { return price; }            set { price = value; }        }    }    class Program    {        static void Main(string[] args)        {            Shoes S1 = new Shoes();            Shoes S2 = new Shoes();            Shoes S3 = S2;            int x = 5;            int y = 8;            int z = x;            object A = 11;            object B = A;            object C = 11;            //內(nèi)容比較            Console.WriteLine(x==y);  //false            Console.WriteLine(x==z);  //true            //裝箱后按引用比較            Console.WriteLine(A==B);  //true            Console.WriteLine(A==C);  //false            //裝箱后按裝箱前類型比較值是否相等            Console.WriteLine(A.Equals(B));  //true            Console.WriteLine(A.Equals(C));  //true            Console.WriteLine(Equals(A, B));  //true            Console.WriteLine(Equals(A, C));  //true            //強(qiáng)制按引用比較            Console.WriteLine(ReferenceEquals(A,B));  //true            Console.WriteLine(ReferenceEquals(A,C));  //false            Console.ReadKey();        }    }}