C#编程模式之享元模式

创作背景：各位朋友，我们继续学习C#的编程模式，本文主要介绍享元模式。享元模式是一种结构型设计模式，它主要用于减少创建对象的数量，从而提高程序性能。它通过共享对象的方式来减少内存的使用，特别是系统中有大量相似对象的时候，这种模式尤其有效。

享元模式的主要组成部分如下：

1、享元对象：享元对象就是被共享的对象，包含很多内部状态，这些状态通常是不变的。

2、享元工厂：负责创建和管理享元对象。

3、非共享状态：每个享元对象的共享状态是特定的，不会被共享。

示例代码如下：

1、创建享元接口。

    /// <summary>/// 享元对象接口/// </summary>public abstract class Flyweight{/// <summary>/// 相关操作/// </summary>/// <param name="strName">名称</param>public abstract string Operation(string strName);}

2、实现共享享元对象。

    /// <summary>/// 实际的享元类（共享状态）/// </summary>public class ActualFlyweight : Flyweight{/// <summary>/// 相关操作/// </summary>/// <param name="strName"></param>/// <returns></returns>/// <exception cref="NotImplementedException"></exception>public override string Operation(string strName){return "创建了ActualFlyweight,名称为:" + strName;}}

3、创建非共享享元对象。

    /// <summary>/// 实际的享元类（非共享）/// </summary>public class UnsharedActualFlyweight : Flyweight{/// <summary>/// 相关操作/// </summary>/// <param name="strName"></param>/// <returns></returns>/// <exception cref="NotImplementedException"></exception>public override string Operation(string strName){return "创建了UnsharedActualFlyweight,名称为:" + strName;}}

4、创建享元工厂。

    /// <summary>/// 享元工厂/// </summary>public class FlyweightFactory{private Hashtable flyweights = new Hashtable();/// <summary>/// 构造函数/// </summary>public FlyweightFactory(){flyweights.Add("One", new ActualFlyweight());flyweights.Add("Two", new ActualFlyweight());flyweights.Add("Three", new ActualFlyweight());}/// <summary>/// 获取Hashtable中的一个享元/// </summary>/// <param name="key"></param>/// <returns></returns>public Flyweight GetFlyweight(string key){return ((Flyweight)flyweights[key]);}}

5、客户端调用。

        /// <summary>/// 享元模式/// </summary>/// <param name="sender"></param>/// <param name="e"></param>private void btn_flyweight_Click(object sender, EventArgs e){FlyweightFactory factory = new FlyweightFactory();Flyweight fx = factory.GetFlyweight("One");tbox_flyweight.Text = fx.Operation("One");Flyweight fy = factory.GetFlyweight("Two");tbox_flyweight.Text += "\r\n" + fy.Operation("Two");Flyweight fz = factory.GetFlyweight("Three");tbox_flyweight.Text += "\r\n" + fz.Operation("Three");UnsharedActualFlyweight fu = new UnsharedActualFlyweight();tbox_flyweight.Text += "\r\n" + fu.Operation("Four");}

6、运行结果图片。