Help_装箱/拆箱后的【==】与【Equals】问题,『★世界第一难题★』,也许只有编译器才能解释清楚_AX
这个能给我讲明白的,绝对是高人了!
代码如下: 如果不清楚可回帖详问.
代码如下: 如果不清楚可回帖详问.
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using System;
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using System.Collections.Generic;
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using System.Text;
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namespace AX
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{
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class AXzhz
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{
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static void Main(string[] args)
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{
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//创建两个string类型的对象,值均为"ii";
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string i = "ii";
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string j = "iii".Substring(1);
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Console.WriteLine("i和j是否同一个对象:"+ReferenceEquals(i,j));//返回:false
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//装箱
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object a = i;
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object b = j;
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//【分析】说明它使用的是object没有重写的"==",即判断引用的是否为同一对象
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Console.WriteLine(a==b);//返回:false
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//【分析】说明它使用的是重写过的object方法Equals(),
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//即string类型的Equals()方法,来判断对象是否为相同内容
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Console.WriteLine(a.Equals(b));//返回:true
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//【问题】string为引用类型无疑,且【==】和【Equals】都已重写(都为比较对象内容是否相同),
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//那为什么装箱后【==】使用没有重写(非重载,只有值类型的才重载,真希望这里是值类型,就可以解释通了)
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//的方法,【Equals】则使用重写过的方法呢?
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/*引自【MSDN】VS2005版
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*在引用类型中实现相等运算符 (==)
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*如果类型是 Point、String、BigNumber 等基类型,则应★重写★相等运算符 (==)。
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* 【附】
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* 改为封装int/char型,结果相同
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* 但可以解释为【==】的重载,即object类型中【==】的原始意思:判断是否引用的同一对象,
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* 而非重载后判断两个对象值是否相同,怎么又回到重写了?晕了,晕了,表妹!!!
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*/
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Console.ReadLine();
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}
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}
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}
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少帮主的斧头好久不饮血了!