C#命令模式  图片来源<设计模式之禅>

 

按上图所示 Receiver是实际干活的实现代码就在这个模块中 , Command 是抽象父类,ConcreteCommand是继承Command的类型 抽象的父类中含有Receiver类 用于子类调用其方法,即子类的Execute就是调用的Receiver中实际代码,Invoker就是为了维护

comand方法 

实际代码如下图

1     /// 
 2     /// 实现类 3     /// 
 4     public class Barbecuer 5     { 6  7         public void BakeMutton() 8         { 9 10             Console.WriteLine("烤羊肉串");11         }12 13         public void BakeChickenWing()14         {15 16             Console.WriteLine("烤鸡翅");17         }18     }

实现类即 Receiver 代码 

//实际代码 public abstract class Command    {//实现代码的类        protected Barbecuer receiver;        public Command(Barbecuer receiver)        {            this.receiver = receiver;        }//实现的方法        abstract public void ExcuteCommand();    }    public class BakeChickenWingCommand : Command    {        public BakeChickenWingCommand(Barbecuer receiver)            : base(receiver)        {        }        public override void ExcuteCommand()        {            receiver.BakeChickenWing();        }    }    public class BakeMuttonCommand : Command    {        public BakeMuttonCommand(Barbecuer receiver)            : base(receiver)        {        }        public override void ExcuteCommand()        {            receiver.BakeMutton();        }    }

上面为父类与子类 即Command  ,ConcreteCommand 模块

 

再来就是维护类 用于维护command方法 

 

public class Waiter    {            Queue queue = new Queue();        public void SetCommand(Command command)        {            queue.Enqueue(command);        }              public void Notify()        {            while (queue.Count > 0)            {                Command command = queue.Dequeue();                command.ExcuteCommand();            }        }    }

 

 

后面调用代码 

class Program    {        static void Main(string[] args)        {            //生成维护的类            Waiter waiter = new Waiter();            //真正实现代码的类            Barbecuer barecuer = new Barbecuer();            //传入到执行类里面去             Command commandwing = new BakeChickenWingCommand(barecuer);            //传入执行的子类 让子类执行代码             waiter.SetCommand(commandwing);            waiter.SetCommand(commandwing);            waiter.SetCommand(commandwing);            waiter.Notify();            Command command = new BakeMuttonCommand(barecuer);            waiter.SetCommand(command);            waiter.SetCommand(command);            waiter.Notify();            Console.ReadKey();        }    }

命令模式 用出就是维护命令的列队,有需要的时候就把命令加入日志,支持撤销与重做 撤销就要在waiter 类 即Invoker模块中进行维护判断是否把command中的某个子类加入到执行列表中