C# 命令模式（Command）

理解：把每个命令封装成一个类，当发令者要发布多个命令时，可以一个个排队地发布给接收者，同时记录下每个命令的详细信息，发布时间等。还可以撤销已发布的命令。

代码：

using System.Collections.Generic;
using System.Windows.Forms;

namespace DesignMode.Command
{
    //被命令者
    public class QQ
    {
        public void Response_SendMessage()
        {
            MessageBox.Show("消息发送中。。。");
        }

        public void Response_PrintScreen()
        {
            MessageBox.Show("截图中。。。");
        }

        public void Response_Remote()
        {
            MessageBox.Show("远程中。。。");
        }
    }

    //抽象命令类
    public abstract class AbstractCommand
    {
        protected QQ _qq;
        public AbstractCommand(QQ qq)
        {
            this._qq = qq;
        }

        public abstract void Execute();
    }

    //发送消息命令类
    public class SendMessageCommand : AbstractCommand
    {
        public SendMessageCommand(QQ qq):base(qq)
        { }

        public override void Execute()
        {
            base._qq.Response_SendMessage();
        }
    }

    //截图命令类
    public class PrintScreenCommand : AbstractCommand
    {
        public PrintScreenCommand(QQ qq):base(qq)
        { }

        public override void Execute()
        {
            base._qq.Response_PrintScreen();
        }
    }

    //远程命令类
    public class RemoteCommand : AbstractCommand
    {
        public RemoteCommand(QQ qq) : base(qq)
        { }

        public override void Execute()
        {
            base._qq.Response_Remote();
        }
    }

    //发号命令者
    public class Me
    {
        IList<AbstractCommand> cmdList = new List<AbstractCommand>();

        //发布命令
        public void IssueCommand(AbstractCommand command)
        {
            cmdList.Add(command);
        }

        //取消命令
        public void CancelCommond(AbstractCommand command)
        {
            cmdList.Remove(command);
        }

        //执行命令
        public void ExecuteCommand()
        {
            foreach (AbstractCommand c in cmdList)
            {
                c.Execute();
            }
        }
    }
}

客户端代码：

        private void btn_Command_Click(object sender, EventArgs e)
        {
            //定义命令承受者
            QQ qq = new QQ();
           
            //定义具体命令
            SendMessageCommand msg = new SendMessageCommand(qq);
            PrintScreenCommand prt = new PrintScreenCommand(qq);
            RemoteCommand remote = new RemoteCommand(qq);
            
            //定义命令发布者
            Me me = new Me();

            //发布命令
            me.IssueCommand(msg);
            me.IssueCommand(prt);
            me.IssueCommand(remote);

            //取消截图命令
            me.CancelCommond(prt);

            //执行命令
            me.ExecuteCommand();
        }