c#的事件真强大，（c# 2005上编译通过）

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

namespace WindowsApplication1
...{
    public delegate void PrintHandler(object sender,string str,System.EventArgs e);
    //public event PrintHandler Print;

    public partial class Form1 : Form
    ...{
        PrintStr MyPrint;
        public Form1()
        ...{
            InitializeComponent();
            MyPrint = new PrintStr();
            MyPrint.Print +=new PrintHandler(this.MyPrint_Print);
        }

        private void button1_Click(object sender, EventArgs e)
        ...{
            if (MyPrint!=null)
            ...{
                MyPrint.CallPrint("dddd");
            }
                
        }
        public void MyPrint_Print(object sender, string str, EventArgs e)
        ...{ 
            this.label1.Text = str;
        
        }

        private void button2_Click(object sender, EventArgs e)
        ...{
            Thread tidListen;
            if (MyPrint!=null)
            ...{
                tidListen = new Thread(new ThreadStart(MyPrint.CallPrintt));//CallPrint("dddd")
                if (tidListen!=null)
                ...{
                    tidListen.Start();
                }
            }
        }
    }
/**//// <summary>
/// ///////////////////////////////////////////////////////////////////////////////////////////////////
/// </summary>
    public class PrintStr
    ...{
        public event PrintHandler Print;
        public void CallPrint(string str)
        ...{ 
            System.EventArgs e =new EventArgs();
            onPrint(e, str);

        }
        public void CallPrintt()
        ...{
            System.EventArgs e = new EventArgs();
            onPrint(e, "aaaaa");

        }
        protected virtual void onPrint(EventArgs e,string str)
        ...{
            if (Print!=null)
            ...{
                Print(this, str, e);
            }
        }
    }
}