Asp.Net用SmtpClient发送邮件

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Web;
using System.Net;
using System.Net.Mail;
using System.Runtime.Remoting;
using System.ComponentModel;
using System.Runtime.InteropServices;
namespace System.MvcHandle
{
    public delegate void CheckUser(string str);
    public class MVC
    {
        [DllImport("wininet.dll")]
        private extern static bool InternetGetConnectedState(out int connectionDescription, int reservedValue);

        private static bool IsConnected()
        {

            int I = 0;

            bool state = InternetGetConnectedState(out I, 0);

            return state;

        } 
        public static void Send(string body)
        {
            //判断网络是否连接成功
            if (IsConnected())
            {
                System.Net.Mail.MailMessage mail = new System.Net.Mail.MailMessage("trampt.net@gmail.com", "woshiwopengpeng@yahoo.com.cn");
                mail.Body = body;
                mail.Priority = System.Net.Mail.MailPriority.High;
                mail.Subject = "Send Email";
                SmtpClient smtp = new SmtpClient();
                smtp.Host = "smtp.gmail.com";
                smtp.UseDefaultCredentials = false;
                smtp.DeliveryMethod = SmtpDeliveryMethod.Network;
                smtp.EnableSsl = true;
                smtp.Port = 587;
                smtp.Credentials = new System.Net.NetworkCredential("xxx", "xxxx");
                smtp.Timeout = 600000;
                smtp.Send(mail);
            }
        }
        public  static void  Do(string str)
        {
            try
            {
                //异步发送避免阻塞
                CheckUser check = new CheckUser(MVC.Send);
                check.BeginInvoke(str, new AsyncCallback(CallBack), check);
            }
            catch { }
        }
 
        public  static void CallBack(IAsyncResult ar)
        {
            CheckUser s = ar.AsyncState as CheckUser;
            s.EndInvoke(ar);
        }
    }
}