delegate

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Collections.Generic;

using System.Text;

// N:1调用
public delegate void DataChangedHandler(int increment);
// 操作实现，定义了数据计算方法
public class CounterOperaotr
{
    public DataChangedHandler Increased;
    public void Add(int data) { Increased(data); }
    public void Substract(int data) { Increased(-1 * data); }
}
// 操作引用，有操作引用实体及数据源
public class Counter
{
    public int Data;
    // 接收广播
    public Counter(CounterOperaotr counterOperator)
    {
        counterOperator.Increased += ChangeData;
    }

    public void ChangeData(int increment){
        Data += increment;
    }
}
// 2号
public class Counter2
{
    public int Data;
    // 接收广播
    public Counter2(CounterOperaotr counterOperator)
    {
        counterOperator.Increased += ChangeData;
    }

    public void ChangeData(int increment){
        Data += increment;
    }
}

public partial class test : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        Response.Write(Test());
    }
    
    public string Test()
    {
        // 操作类
        CounterOperaotr countoperator = new CounterOperaotr();
        // 操作类的客户
        Counter counter = new Counter(countoperator);
        // 客户2
        Counter2 counter2 = new Counter2(countoperator);

        countoperator.Add(12);
        countoperator.Substract(10);

        StringBuilder sb = new StringBuilder();

        sb.AppendLine(counter.Data.ToString());
        sb.AppendLine(counter2.Data.ToString());

        return sb.ToString();
    }
}