設計模式學習筆記-策略模式

策略模式：Strategy,它定義了演算法家族，分別封裝起來，讓他們之間可以相互替換，讓演算法的變化不會影響到演算法使用者

1.定義抽象演算法

    /// <summary>
/// 抽象演算法類
/// </summary>
    abstract class Strategy
    {
/// <summary>
/// 演算法方法 介面定義
/// </summary>
        public abstract void AlgorithmInterface();
    }

2.具體演算法的實現

  /// <summary>
/// 具體演算法A
/// </summary>
    class ConcreteStrategyA : Strategy 
    {
public override void AlgorithmInterface() 
        {
            Console.WriteLine("演算法A的實現");
        }
    }
/// <summary>
/// 具體演算法B
/// </summary>
    class ConcreteStrategyB : Strategy
    {
public override void AlgorithmInterface()
        {
            Console.WriteLine("演算法B的實現");
        }
    }
/// <summary>
/// 具體演算法C
/// </summary>
    class ConcreteStrategyC : Strategy
    {
public override void AlgorithmInterface()
        {
            Console.WriteLine("演算法C的實現");
        }
    }

3.調度類

    /// <summary>
/// 承上啟下的演算法調用
/// </summary>
    class Context 
    {
        Strategy strategy;
/// <summary>
/// 傳入具體策略對象
/// </summary>
/// <param name="strategy"></param>
        public Context(Strategy strategy) 
        {
this.strategy = strategy;
        }
/// <summary>
/// 根據策略對象的值判斷調用的演算法類
/// </summary>
        public void ContextInterface() 
        {
            strategy.AlgorithmInterface();
        }
    }

　　用戶端調用：

        /// <summary>
/// 測試策略
/// </summary>
        static void TestStrategy() 
        {
            Context context;
//策略A
            context = new Context(new ConcreteStrategyA());
            context.ContextInterface();
//策略B
            context = new Context(new ConcreteStrategyB());
            context.ContextInterface();
//策略C
            context = new Context(new ConcreteStrategyC());
            context.ContextInterface();
            Console.Read();
        }

　　策略模式比較簡單但是應用非常的多