C# 原型模式讲解和代码示例
原型是一种创建型设计模式， 使你能够复制对象， 甚至是复杂对象， 而又无需使代码依赖它们所属的类。
所有的原型类都必须有一个通用的接口， 使得即使在对象所属的具体类未知的情况下也能复制对象。 原型对象可以生成自身的完整副本， 因为相同类的对象可以相互访问对方的私有成员变量。
复杂度：
流行度：
使用示例： C# 的 ICloneable （克隆） 接口就是立即可用的原型模式。
识别方法： 原型可以简单地通过 clone或 copy等方法来识别。
概念示例
本例说明了原型设计模式的结构并重点回答了下面的问题：
- 它由哪些类组成？
- 这些类扮演了哪些角色？
- 模式中的各个元素会以何种方式相互关联？
Program.cs: 概念示例
using System;
namespace RefactoringGuru.DesignPatterns.Prototype.Conceptual
{
public class Person
{
public int Age;
public DateTime BirthDate;
public string Name;
public IdInfo IdInfo;
public Person ShallowCopy()
{
return (Person) this.MemberwiseClone();
}
public Person DeepCopy()
{
Person clone = (Person) this.MemberwiseClone();
clone.IdInfo = new IdInfo(IdInfo.IdNumber);
clone.Name = String.Copy(Name);
return clone;
}
}
public class IdInfo
{
public int IdNumber;
public IdInfo(int idNumber)
{
this.IdNumber = idNumber;
}
}
class Program
{
static void Main(string[] args)
{
Person p1 = new Person();
p1.Age = 42;
p1.BirthDate = Convert.ToDateTime("1977-01-01");
p1.Name = "Jack Daniels";
p1.IdInfo = new IdInfo(666);
// Perform a shallow copy of p1 and assign it to p2.
Person p2 = p1.ShallowCopy();
// Make a deep copy of p1 and assign it to p3.
Person p3 = p1.DeepCopy();
// Display values of p1, p2 and p3.
Console.WriteLine("Original values of p1, p2, p3:");
Console.WriteLine(" p1 instance values: ");
DisplayValues(p1);
Console.WriteLine(" p2 instance values:");
DisplayValues(p2);
Console.WriteLine(" p3 instance values:");
DisplayValues(p3);
// Change the value of p1 properties and display the values of p1,
// p2 and p3.
p1.Age = 32;
p1.BirthDate = Convert.ToDateTime("1900-01-01");
p1.Name = "Frank";
p1.IdInfo.IdNumber = 7878;
Console.WriteLine("\nValues of p1, p2 and p3 after changes to p1:");
Console.WriteLine(" p1 instance values: ");
DisplayValues(p1);
Console.WriteLine(" p2 instance values (reference values have changed):");
DisplayValues(p2);
Console.WriteLine(" p3 instance values (everything was kept the same):");
DisplayValues(p3);
}
public static void DisplayValues(Person p)
{
Console.WriteLine(" Name: {0:s}, Age: {1:d}, BirthDate: {2:MM/dd/yy}",
p.Name, p.Age, p.BirthDate);
Console.WriteLine(" ID#: {0:d}", p.IdInfo.IdNumber);
}
}
}
Output.txt: 执行结果
Original values of p1, p2, p3:
p1 instance values:
Name: Jack Daniels, Age: 42, BirthDate: 01/01/77
ID#: 666
p2 instance values:
Name: Jack Daniels, Age: 42, BirthDate: 01/01/77
ID#: 666
p3 instance values:
Name: Jack Daniels, Age: 42, BirthDate: 01/01/77
ID#: 666
Values of p1, p2 and p3 after changes to p1:
p1 instance values:
Name: Frank, Age: 32, BirthDate: 01/01/00
ID#: 7878
p2 instance values (reference values have changed):
Name: Jack Daniels, Age: 42, BirthDate: 01/01/77
ID#: 7878
p3 instance values (everything was kept the same):
Name: Jack Daniels, Age: 42, BirthDate: 01/01/77
ID#: 666
