读书笔记18：命令模式

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1、定义：
将一个请求封装为一个对象，从而使你可用不同的请求对客户进行参数化；对请求排队或记录请求日志，以及支持可撤消的操作。[GOF 《设计模式》]
2、角色
Command——用来执行操作的接口。
CreateCommand——将一个接收者对象绑定一个动作，并实现执行命令操作。
Invoker——要求该命令执行。
Receiver——知道如何实施与执行一个与请求相关的操作，任何类都可作为一个接收者。
3、模型
Command

  abstract class Command    {        protected Receiver receiver;        public Command(Receiver creceiver)        {            this.receiver = creceiver;        }        abstract public void Execute();    }

CreateCommand

class CreateCommand : Command    {        public CreateCommand(Receiver receiver)            : base(receiver)        {        }        public override void Execute()        {            receiver.Action();        }    }

Receiver

  class Receiver    {        public void Action()        {            Console.WriteLine("执行命令");        }    }

Invoker

    class Invoker    {        private Command command;        public void SetCommand(Command command)        {            this.command = command;        }        public void ExecuteCommand()        {            command.Execute();        }    }

调用

        static void Main(string[] args)        {            Receiver receiver = new Receiver();            Command command = new CreateCommand(receiver);            Invoker invoker = new Invoker();            invoker.SetCommand(command);            invoker.ExecuteCommand();            Console.ReadLine();        }

结果：

命令模式模型代码：http://download.csdn.net/detail/yysyangyangyangshan/4089536

命令模式，很多个Receiver，并与之对应Command也有很多个，Invoker则负责将Receiver和Command关联，并执行。

应用模型：

    abstract class Command1    {        protected Receiver1 receiver1;        public Command1(Receiver1 creceiver1)        {            this.receiver1 = creceiver1;        }        abstract public void Execute();    }        abstract class Command2    {        protected Receiver2 receiver2;        public Command2(Receiver2 creceiver2)        {            this.receiver2 = creceiver2;        }        abstract public void Execute();    }        class CreateCommand1 : Command1    {        public CreateCommand1(Receiver1 receiver1)            : base(receiver1)        {        }        public override void Execute()        {            receiver1.Action();        }    }        class CreateCommand2 : Command2    {        public CreateCommand2(Receiver2 receiver2)            : base(receiver2)        {        }        public override void Execute()        {            receiver2.Action();        }    }        class Invoker    {        private Command1 command1;        private Command2 command2;        public void SetCommand1(Command1 command)        {            this.command1 = command;        }        public void ExecuteCommand1()        {            command1.Execute();        }        public void SetCommand2(Command2 command)        {            this.command2 = command;        }        public void ExecuteCommand2()        {            command2.Execute();        }    }        class Receiver1    {        public void Action()        {            Console.WriteLine("执行命令一");        }    }        class Receiver2    {        public void Action()        {            Console.WriteLine("执行命令二");        }    }

调用

        static void Main(string[] args)        {            Receiver1 receiver1 = new Receiver1();            Receiver2 receiver2 = new Receiver2();            Command1 command1 = new CreateCommand1(receiver1);            Command2 command2 = new CreateCommand2(receiver2);            Invoker invoker = new Invoker();            invoker.SetCommand1(command1);            invoker.ExecuteCommand1();            invoker.SetCommand2(command2);            invoker.ExecuteCommand2();            Console.ReadLine();        }

结果：

应用代码：http://download.csdn.net/detail/yysyangyangyangshan/4089547