C# 设计模式（16）命令模式

命令模式

1. 实现异步队列

2.数据恢复，命令撤销

代码实现：

对象：

namespace CommandPattern
{
    public class Document
    {
        public int Id { get; set; }
        public string Name { get; set; }
    }
}

行为：

    public abstract class BaseCommand
    {
        protected  Document Document =null;
        protected Receiver Receiver = null;

        public void SetDocument(Document document)
        {
            this.Document = document;
        }

        public void SetReceiver(Receiver receiver)
        {
            this.Receiver = receiver;
        }

        public abstract void Execute();
    }
    public class ReadCommand : BaseCommand
    {
        public override void Execute()
        {
            Receiver.Name = Document.Name;
            Receiver.Read();
        }
    }
    class WriteCommand:BaseCommand
    {
        public override void Execute()
        {
            Receiver.Name = Document.Name;
            Receiver.Write();
        }
    }

执行者：

    public class Receiver
    {
        public string Name { get; set; }
        public void Write()
        {
            Console.WriteLine($"{Name} Write Data...");
        }
        public void Read()
        {
            Console.WriteLine($"{Name} Read Data...");
        }
    }

代码调用：

    class Program
    {
        static void Main(string[] args)
        {
            Document doc = new Document()
            {
                Id=01,
                Name = "Action1"
            };

            while (true)
            {
                Console.WriteLine("Please Insert Command W or R");
                string input = Console.ReadLine();
                var instance = ConfigurationManager.AppSettings[input].Split(',')[1];
                var method = ConfigurationManager.AppSettings[input].Split(',')[0];
                BaseCommand cmd = (BaseCommand) Activator.CreateInstance(instance, method).Unwrap();
                Receiver receiver = new Receiver();
                cmd.SetReceiver(receiver);
                cmd.SetDocument(doc);
                cmd.Execute();
            }
        }
    }

结果：