讀書筆記18：命令模式

 1、定義：
將一個請求封裝為一個對象，從而使你可用不同的請求對客戶進行參數化；對請求排隊或記錄請求日誌，以及支援可撤消的操作。[GOF 《設計模式》]
2、角色
Command——用來執行操作的介面。
CreateCommand——將一個接收者對象綁定一個動作，並實現執行命令操作。
Invoker——要求該命令執行。
Receiver——知道如何實施與執行一個與請求相關的操作，任何類都可作為一個接收者。
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("執行命令");        }    } 

Invoker

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

調用

        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();        }

結果：

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

命令模式，很多個Receiver，並與之對應Command也有很多個，Invoker則負責將Receiver和Command關聯，並執行。

應用程式模型：

    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("執行命令一");        }    }        class Receiver2    {        public void Action()        {            Console.WriteLine("執行命令二");        }    }

調用

        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();        }

結果：

  
應用代碼：http://download.csdn.net/detail/yysyangyangyangshan/4089547