策略模式（Stratety）

namespace StrategyPattern //策略模式
{
    /// <summary>
    /// 定義所以支持的演算法的公共介面
    /// </summary>
    abstract  class Strategy
    {
        /// <summary>
        /// 演算法方法。
        /// </summary>
        public abstract void AlgorithmInrerface();
    }

    class ConcreateStratetyA : Strategy
    {
        public override void AlgorithmInrerface()
        {
            Console.WriteLine("實現演算法A"); 
        }
    }

    class ConcreateStratetyB : Strategy
    {
        public override void AlgorithmInrerface()
        {
            Console.WriteLine("實現演算法B");
        }
    }

    class ConcreateStratetyC : Strategy
    {
        public override void AlgorithmInrerface()
        {
            Console.WriteLine("實現演算法C");
        }
    }

    /// <summary>
    /// 用一個ConcreateStratety來配置，來維護一個對Stratety對象的引用。
    /// </summary>
    class Context
    {
        Strategy stratety;
        public Context(Strategy stratety)//構造器註入具體的策略對象。    
        {
            this.stratety = stratety;
        }
        /// <summary>
        /// 根據具體策略的對象，調用其演算法的方法。
        /// </summary>
        public void ContextInterface()
        {
            stratety.AlgorithmInrerface();
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            Context context = null;

            context = new Context(new ConcreateStratetyA());
            context.ContextInterface();


            context = new Context(new ConcreateStratetyB());
            context.ContextInterface();


            context = new Context(new ConcreateStratetyC());
            context.ContextInterface();

            Console.Read();
        }
    }
}