C# 享元模式（Flyweight）

理解：有大量相同类型对象需要创造出来时，可以一种类型只保存一个实例，可以改它的外部状态（如位置，名称等）

代码：

using System.Collections;
using System.Windows.Forms;

namespace DesignMode.Flyweight
{
    //抽象棋子类
    public abstract class Chessman
    {
        public abstract void Move(int x,int y);
         
    }

    //白棋子
    public class White_Chessman : Chessman
    {
        public override void Move(int x,int y)
        {
            MessageBox.Show("白棋下在：X=" + x + ",Y=" + y);
        }
    }

    //黑棋子
    public class Black_Chessman : Chessman
    {
        public override void Move(int x, int y)
        {
            MessageBox.Show("黑棋下在：X=" + x + ",Y=" + y);
        }
    }


    public class ChessmanFactory
    {
        private Hashtable chessmans = new Hashtable();

        public Chessman GetChessman(string color)
        {
            if (!chessmans.ContainsKey(color))
            {
                if (color.Equals("白"))
                {
                    chessmans.Add(color, new White_Chessman());
                }
                else
                {
                    chessmans.Add(color, new Black_Chessman());
                }

            }

            return (Chessman)chessmans[color];
        }
    }} 

 客户端代码：

       

         private void btn_Flyweight_Click(object sender, EventArgs e)

 {
            ChessmanFactory factory = new ChessmanFactory();
            Chessman white1 = factory.GetChessman("白");
            white1.Move(5, 10);

            Chessman black1 = factory.GetChessman("黑");
            black1.Move(6, 12);

            Chessman white2 = factory.GetChessman("白");
            white2.Move(7, 14);

            Chessman black2 = factory.GetChessman("黑");
            black2.Move(10, 18);
        }