原型模式就是依照样本复制一个出来。就像复印机原理一样的。当你需要一个同样的对象时。你并不需要重新构建这个类。你直接使用CLONE就可以得到这个类。
在实际编程中，由于在某些情况下构建一个对象很难，这个时候你就要用到原型模式了，直接复制。
复制分为两种
1、深度复制
深度复制就是，值类型和引用类型都同时指向不同的内存地址
2、浅复制
浅复制就是，值类型是新内存地址，而引用类型是同一个内存地址，因此你修改了值类型正本和副本相互不影响，你修改了引用类型正本和副本相互影响。
两种复制方法在实际当中的使用：
public class IdInfo
{
public int IdNumber;
public IdInfo(int IdNumber)
{
this.IdNumber = IdNumber;
}
}
public class Person
{
public int Age;
public string Name;
public IdInfo IdInfo;
/// <summary>
/// 浅复制
/// </summary>
/// <returns></returns>
public Person ShallowCopy()
{
return (Person)this.MemberwiseClone();
}
/// <summary>
/// 深复制
/// </summary>
/// <returns></returns>
public Person DeepCopy()
{
Person other = (Person)this.MemberwiseClone();
other.IdInfo = new IdInfo(IdInfo.IdNumber);
other.Name = String.Copy(Name);
return other;
}
}
结果测试：
static void Main(string[] args)
{
// Create an instance of Person and assign values to its fields.
Person p1 = new Person();
p1.Age = 42;
p1.Name = "山姆";
p1.IdInfo = new IdInfo(6565);
// Perform a shallow copy of p1 and assign it to p2.
Person p2 = p1.ShallowCopy();
// Display values of p1, p2
Console.WriteLine("Original values of p1 and p2:");
Console.WriteLine(" p1 instance values: ");
DisplayValues(p1);
Console.WriteLine(" p2 instance values:");
DisplayValues(p2);
// Change the value of p1 properties and display the values of p1 and p2.
p1.Age = 32;
p2.Age = 42;
p1.Name = "山姆";
p2.Name = "王小小";
p2.IdInfo.IdNumber = 7878;
p1.IdInfo.IdNumber = 9898;
Console.WriteLine("\nValues of p1 and p2 after changes to p1:");
Console.WriteLine(" p1 instance values: ");
DisplayValues(p1);
Console.WriteLine(" p2 instance values:");
DisplayValues(p2);
// Make a deep copy of p1 and assign it to p3.
Person p3 = p1.DeepCopy();
// Change the members of the p1 class to new values to show the deep copy.
p1.Name = "乔治";
p1.Age = 39;
p1.IdInfo.IdNumber = 8641;
Console.WriteLine("\nValues of p1 and p3 after changes to p1:");
Console.WriteLine(" p1 instance values: ");
DisplayValues(p1);
Console.WriteLine(" p3 instance values:");
DisplayValues(p3);
Console.Read();
}
public static void DisplayValues(Person p)
{
Console.WriteLine(" Name: {0:s}, Age: {1:d}", p.Name, p.Age);
Console.WriteLine(" Value: {0:d}", p.IdInfo.IdNumber);
}
运行结果：
描述：
.NET Freamwork 内置的每个继承自System.Object都有保护成员方法：
[SecuritySafeCritical]
protected object MemberwiseClone();
.NET给我提供了一个System.ICloneable的接口，我们通过实现这个接口，可以为对象提供自定义的克隆方法。
/// <summary>
/// 杯子类
/// </summary>
public class Cup : ICloneable
{
/// <summary>
/// 生产厂家
/// </summary>
public Factory Factory
{
get {return _factory;}
set {_factory = value;}
}
#region ICloneable 成员
public object Clone()
{
return this.MemberwiseClone();
}
#endregion
}
static void Main(string[] args)
{
Cup cup = new Cup();
cup.Height = 2;
Cup cup1 = (Cup)cup.Clone();
cup1.Height = 1;
Console.WriteLine(cup.Height == cup1.Height);
}
通过序列化的形式来进行对象的复制
/// <summary>
/// 序列化和反序列化辅助类
/// </summary>
public class SerializableHelper
{
public string Serializable(object target)
{
using (MemoryStream stream = new MemoryStream())
{
new BinaryFormatter().Serialize(stream, target);
return Convert.ToBase64String(stream.ToArray());
}
}
public object Derializable(string target)
{
byte[] targetArray = Convert.FromBase64String(target);
using (MemoryStream stream = new MemoryStream(targetArray))
{
return new BinaryFormatter().Deserialize(stream);
}
}
public T Derializable<T>(string target)
{
return (T)Derializable(target);
}
}
///在类中实例CLONE接口
#region IColorDemo 成员
public IColorDemo Clone()
{
string target= SerializableHelper.Serializable(this);
return SerializableHelper.Derializable<IColorDemo>(target);
}
#endregion
通过二进制序列化来进行复制，都是深复制。
参考文档：
http://www.cnblogs.com/siqing99/archive/2012/04/03/2430918.html
http://www.cnblogs.com/hegezhou_hot/archive/2010/12/04/1896471.html
https://msdn.microsoft.com/zh-cn/library/system.object.memberwiseclone.aspx
原文：http://www.cnblogs.com/lystory/p/5067253.html