正确的方式来实现ICloneable [英] Proper way to implement ICloneable

问题描述

什么是类层次实施 ICloneable 的正确方法是什么？说我有一个抽象类 DrawingObject 。另一个抽象类的RectangularObject 从 DrawingObject 继承。随后有多个具体类，如图形，文本，圆等等，所有从的RectangularObject 。我想实施 ICloneable 在 DrawingObject 然后再进行下来的层次，每个层次复制可用的属性，并呼吁家长的克隆在一个新的水平。

What is the proper way of implementing ICloneable in a class hierarchy? Say I have an abstract class DrawingObject. Another abstract class RectangularObject inherits from DrawingObject. Then there are multiple concrete classes like Shape, Text, Circle etc. that all inherit from RectangularObject. I want to implement ICloneable on DrawingObject and then carry it down the hierarchy, copying available properties at each level and calling parent's Clone at the next level.

但问题是，既然前两个类是抽象的，我不能在克隆（）方法来创建自己的对象。因此，我必须复制在每个具体的类属性复制过程。还是有更好的办法吗？

The problem however is that since the first two classes are abstract, I cannot create their objects in the Clone() method. Thus I must duplicate the property-copying procedure in each concrete class. Or is there a better way?

推荐答案

您可以轻松地创建带有对象的保护方法<一个肤浅的克隆href="http://msdn.microsoft.com/en-us/library/system.object.memberwiseclone%28v=vs.110%29.aspx">MemberwiseClone.

You can easily create a superficial clone with object's protected method MemberwiseClone.

例：

   public abstract class AbstractCloneable : ICloneable
   {
      public object Clone()
      {
         return this.MemberwiseClone();
      }
   }

如果你并不需要像深拷贝什么，你就不必在子类做任何事情。

If you don't need anything like a deep copy, you will not have to do anything in the child classes.

的MemberwiseClone方法创建一个新的对象，然后复制当前对象的非静态字段到新的对象创建一个浅表副本。如果一个字段是值类型，执行字段的位逐位拷贝。如果字段是引用类型，引用复制的，但被引用的对象不是;因此，原来的对象及其克隆指代相同的对象。

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.

如果您在克隆逻辑需要更多的智慧，你可以添加一个虚拟的方法来处理参考文献：

If you need more intelligence in the cloning logic, you can add a virtual method to handle references :

   public abstract class AbstractCloneable : ICloneable
   {
      public object Clone()
      {
         var clone = (AbstractCloneable) this.MemberwiseClone();
         HandleCloned(clone);
         return clone;
      }

      protected virtual HandleCloned(AbstractCloneable clone)
      {
         //Nothing particular in the base class, but maybe usefull for childs.
         //Not abstract so childs may not implement this if they don't need to.
      }

   }


   public class ConcreteCloneable : AbstractCloneable
   {
       protected override HandleCloned(AbstractCloneable clone)
       {
           //Get wathever magic a base class could have implemented.
           base.HandleCloned(clone);

           //Clone is of the current type.
           ConcreteCloneable obj = (ConcreteCloneable) clone;

           //Here you have a superficial copy of "this". You can do wathever 
           //specific task you need to do.
           //e.g.:
           obj.SomeReferencedPropertie = this.SomeReferencedPropertie.Clone();
       }
   }

这篇关于正确的方式来实现ICloneable的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！