MemberwiseClone（）的方法是做什么的？ [英] What is the method MemberwiseClone() doing?

问题描述

我对下面的代码感到困惑，

I am confused with this code below,

Developer devCopy = (Developer)dev.Clone();

Developer类的克隆方法只是创建一个Employee克隆，然后开发人员如何获得另一个开发人员克隆。

Clone method of Developer class just creating a Employee clone, then how developer get another clone of developer.

public abstract class Employee
{
    public abstract Employee Clone();

    public string Name { get; set; }
    public string Role { get; set; }
}


public class Typist : Employee
{
    public int WordsPerMinute { get; set; }

    public override Employee Clone()
    {
        return (Employee)MemberwiseClone();
    }

    public override string ToString()
    {
        return string.Format("{0} - {1} - {2}wpm", Name, Role, WordsPerMinute);
    }
}


public class Developer : Employee
{
    public string PreferredLanguage { get; set; }

    public override Employee Clone()
    {
        return (Employee)MemberwiseClone();
    }

    public override string ToString()
    {
        return string.Format("{0} - {1} - {2}", Name, Role, PreferredLanguage);
    }
}


Developer dev = new Developer();
dev.Name = "Bob";
dev.Role = "Team Leader";
dev.PreferredLanguage = "C#";

Developer devCopy = (Developer)dev.Clone();
devCopy.Name = "Sue";

Console.WriteLine(dev);
Console.WriteLine(devCopy);

/* OUTPUT

Bob - Team Leader - C#
Sue - Team Leader - C#

*/

Typist typist = new Typist();
typist.Name = "Kay";
typist.Role = "Typist";
typist.WordsPerMinute = 120;

Typist typistCopy = (Typist)typist.Clone();
typistCopy.Name = "Tim";
typistCopy.WordsPerMinute = 115;

Console.WriteLine(typist);
Console.WriteLine(typistCopy);

/* OUTPUT

Kay - Typist - 120wpm
Tim - Typist - 115wpm

*/

推荐答案

因为方法 MemberwiseClone（）正在为您执行此操作。请参见文档

Because the method MemberwiseClone() is doing this for you. See the documentation

MemberwiseClone方法通过创建新对象，然后将当前对象的非静态字段复制到新对象来创建浅表副本。如果字段是值类型，则将执行该字段的逐位复制。如果字段是引用类型，则引用被复制，但引用的对象则不是。因此，原始对象及其克隆引用的是同一对象。

The MemberwiseClone method creates a shallow copy by creating a new object, and then copying the nonstatic fields of the current object to the new object. If a field is a value type, a bit-by-bit copy of the field is performed. If a field is a reference type, the reference is copied but the referred object is not; therefore, the original object and its clone refer to the same object.

每当您看到不理解的方法时，都可以跟踪谁声明了它（我想是在Visual Studio中），然后查看其文档。在大多数情况下，这使事情变得显而易见。

Whenever you see a method you don't unerstand, you can trace who has declared it (in Visual Studio, I guess), and in turn see its documentation. That makes things pretty obvious most of the time.

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