观察者设计模式代码

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace _04PublishPatten
{

    public partial class MainFrm : Form
    {
        public ChildFrm1 ChildFrm1 { get; set; }
        public MainFrm()
        {
            InitializeComponent();
        }

        private void btnOpenFrms_Click(object sender, EventArgs e)
        {
            ChildFrm1 frm1 =new ChildFrm1();

            this.ChildFrm1 = frm1;

            frm1.Show();


            ChildFrm2 frm2 = new ChildFrm2();
            //第一种：用接口的形式注册 观察者。
            frm1.MessageOnList.Add(frm2);//把观察者放到  观察者的集合中。

            //第二种：用户委托的形式注册观察者
            //观察者的 方法注册到  form1窗体的委托中去。
            //frm1.SendMsgDelInstance += frm2.SetMsgText;

            //第三种：事件的形式注册观察者。
            frm1.SendMsgDelEvent += frm2.SetMsgTextEvent;

            frm2.Show();


            ChildFrm3 frm3 = new ChildFrm3();
            //frm1.MessageOnList.Add(frm3);
            frm1.SendMsgDelInstance += frm3.SetMsgText;

            frm1.SendMsgDelEvent += frm3.SetMsgTextEvent;
            frm3.Show();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            this.ChildFrm1.SendMsgDelInstance("ssssss");
            //this.ChildFrm1.SendMsgDelEvent("sssss");
        }
    }
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _04PublishPatten
{
    public interface IMessageON
    {
        void RecieveMsg(string str);
    }
}
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace _04PublishPatten
{
    public partial class ChildFrm3 : Form,IMessageON
    {
        public ChildFrm3()
        {
            InitializeComponent();
        }

        #region 接口实现观察者模式的方法
        public void RecieveMsg(string str)
        {
            this.txtMsg.Text = str + "     " + DateTime.Now.ToString();
        } 
        #endregion


        #region 委托实现的观察者的方法

        public void SetMsgText(string str)
        {
            this.txtMsg.Text ="委托："+ str;
        }
        #endregion


        #region 事件使用的方法

        public void SetMsgTextEvent(string str)
        {
            this.txtMsg.Text = " 事件：" + str;
        }
        #endregion
    }
}
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace _04PublishPatten
{
    public partial class ChildFrm2 : Form,IMessageON
    {
        public ChildFrm2()
        {
            InitializeComponent();
        }

        #region 接口实现观察者模式的方法

        public void RecieveMsg(string str)
        {
            this.txtMessage.Text = str + "    " + DateTime.Now.ToString();
        }
        
        #endregion

        #region 委托使用的方法

        public void SetMsgText(string str)
        {
            this.txtMessage.Text = " 委托：" + str;
        }
        #endregion


        #region 事件使用的方法

        public void SetMsgTextEvent(string str)
        {
            this.txtMessage.Text = " 事件：" + str;
        }
        #endregion
    }
}
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace _04PublishPatten
{
    public delegate void SendMsgDel(string strMsg);

    public partial class ChildFrm1 : Form
    {
        public ChildFrm1()
        {
            InitializeComponent();
            MessageOnList = new List<IMessageON>();
        }

        #region 委托实现观察者模式
        public SendMsgDel SendMsgDelInstance { get; set; }
        private void btnDelSendMsg_Click(object sender, EventArgs e)
        {
            SendMsgDelInstance(DateTime.Now.ToString());
        }
        #endregion

        #region 用事件实现观察者模式

        public event SendMsgDel SendMsgDelEvent;

        private void btnEvent_Click(object sender, EventArgs e)
        {
            SendMsgDelEvent(DateTime.Now.ToString() + "   ---");
        }

        #endregion

        #region C#代码实现观察者模式
        //这个集合放我们的观察者。
        public List<IMessageON> MessageOnList { get; set; }

        private void btnMessage_Click(object sender, EventArgs e)
        {
            foreach (var messageOn in MessageOnList)
            {
                messageOn.RecieveMsg("------");
            }
        }
        #endregion

  
   
    }
}