观察者模式--初学入门

理解不是很深，不做解说，自己写了个小例子记录下来

例子以面试者去面试为主题，容易理解，例子简单(小白写的，能不简单吗),能看的懂的代码才是好代码啊

观察者接口

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    /// <summary>
    /// 观察者接口
    /// </summary>
    interface IMSG
    {
        /// <summary>
        /// 出题
        /// </summary>
        void ShowMessage();
        /// <summary>
        /// 结果
        /// </summary>
        void Result();
    }
}

观察者

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    /// <summary>
    /// 面试管
    /// </summary>
    public class MSG : IMSG
    {
        /// <summary>
        /// 面试状态
        /// </summary>
        public string state { get; set; }
        public GCZ_abstract gcz { get; set; }//面试者
        private List<GCZ_abstract> works = new List<GCZ_abstract>();//所有面试人员
        /// <summary>
        /// 添加面试人员
        /// </summary>
        /// <param name="gcz"></param>
        public void Add(GCZ_abstract gcz)
        {
            works.Add(gcz);
        }
        /// <summary>
        /// 删除面试人员
        /// </summary>
        /// <param name="gcz"></param>
        public void Remove(GCZ_abstract gcz)
        {
            works.Remove(gcz);
        }
        public void ShowMessage()
        {
            Console.WriteLine("欢迎来面试，我出题了。。。\n");
        }

        /// <summary>
        /// 面试结果
        /// </summary>
        public void Result()
        {
            foreach(GCZ_abstract man in works)
            {
                man.GX();
            }
        }
    }
}

订阅类型

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    /// <summary>
    /// 面试人员集合
    /// </summary>
    public abstract class GCZ_abstract
    {
        /// <summary>
        /// 面试感想
        /// </summary>
        public abstract void GX();
    }
}

类型一(订阅者)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    /// <summary>
    /// 具体观察者类型(面试人员)
    /// </summary>
    public class GCZ1 : GCZ_abstract
    {
        private MSG msg { get; set; }
        public GCZ1(MSG msg)
        {
            this.msg = msg;
        }

        public override void GX()
        {
            if (msg.state == "1")
            {
                Console.WriteLine("面试官来了，很激动！");
            }
            else if (msg.state == "2") 
            {
                Console.WriteLine("面试官还没来，很紧张！");
            }
            else
                Console.WriteLine("面试官结束了，轻松！");
        }
    }
}

类型二(订阅者)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    /// <summary>
    /// 具体观察者类型(面试人员)
    /// </summary>
    public class GCZ2 : GCZ_abstract
    {
        private MSG msg { get; set; }
        public GCZ2(MSG msg)
        {
            this.msg = msg;
        }

        public override void GX()
        {
            if (msg.state == "1")
            {
                Console.WriteLine("面试官来了，我不动明王！");
            }
            else if (msg.state == "2")
            {
                Console.WriteLine("面试官还没来，我不动明王！");
            }
            else
                Console.WriteLine("面试结束，我面不改色！");
        }
    }
}

结果

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            MSG msg = new MSG();//面试的面试官
            msg.ShowMessage();//面试官出题
            //面试中
            GCZ1 one = new GCZ1(msg);//面试者1
            msg.Add(one);
            GCZ2 two = new GCZ2(msg);//面试者2
            msg.Add(two);

            msg.state = "2";//面试状态
            msg.Result();
        }
    }
}