关于异步委托的调用与应用场景

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Threading;

using System.Runtime.Remoting.Messaging;

using System.IO;



namespace TestApp.ResponseHeader

{

    public partial class Demo : System.Web.UI.Page

    {

        public delegate void SendMailHandler();

        protected void Page_Load(object sender, EventArgs e)

        {

            Response.ClearHeaders();

            Response.AddHeader("Server", "nginx");

            Response.AddHeader("testID", Session.SessionID);

        }



        protected void Button1_Click(object sender, EventArgs e)

        {

            string userName = this.TextBox1.Text;

            Response.Write(string.Format("当前注册的用户是:{0}",userName));



            SendMailHandler sendMailHandler = new SendMailHandler(SendMail);

            AsyncCallback callBack = new AsyncCallback(SendMailCallBack);

            sendMailHandler.BeginInvoke(callBack, userName);

        }





        public void SendMailCallBack(IAsyncResult re)

        {

            AsyncResult result = re as AsyncResult;

            SendMailHandler handler = (SendMailHandler)result.AsyncDelegate;

            handler.EndInvoke(re);



            WriteLog(string.Format("{0},您的注册邮件已经发送...", re.AsyncState));

            WriteLog(string.Format("{0}::邮件发送完毕...", DateTime.Now));

        }



        private void SendMail()

        {

            WriteLog(string.Format("{0}::开始发送邮件...", DateTime.Now));

            Thread.Sleep(20000);



            //ThreadStart ts = new ThreadStart(Run);



            string s = "gogogo...";

            ParameterizedThreadStart pts = new ParameterizedThreadStart(Run);

            Thread t = new Thread(pts);

            t.Start(s);

        }



        private void WriteLog(string log)

        {

           StreamWriter sw = File.AppendText(Server.MapPath("~/text.txt"));

           sw.WriteLine(log);

           sw.Flush();

           sw.Close();

        }





        public void Run(object s)

        {

            WriteLog(s.ToString());

        }

    }

}

结果如下图