１.源码：

 public class CSendMail

    {

        private MailMessage mailMessage;

        private SmtpClient smtpClient;

        private string password;//发件人密码 

        //邮件发送后提醒

        public String Info

        {

            get;

            set;

        }

        /// <summary>

        /// 处审核后类的实例

        /// </summary>

        /// <param name="To">收件人地址</param>

        /// <param name="From">发件人地址</param>

        /// <param name="Body">邮件正文</param>

        /// <param name="Title">邮件的主题</param>

        /// <param name="Password">发件人密码</param>

        public CSendMail(string To, string From, string Body, string Title, string

                       Password)

        {

            mailMessage = new MailMessage();

            mailMessage.To.Add(To);

            mailMessage.From = new System.Net.Mail.MailAddress(From);

            mailMessage.Subject = Title;

            mailMessage.Body = Body;

            mailMessage.IsBodyHtml = true;

            mailMessage.BodyEncoding = System.Text.Encoding.UTF8;

            mailMessage.Priority = System.Net.Mail.MailPriority.Normal;

            this.password = Password;

        }

        /// <summary>

        /// 添加附件

        /// </summary>

        public void Attachments(string Path)

        {

            string[] path = Path.Split(',');

            Attachment data;

            ContentDisposition disposition;

            for (int i = ; i < path.Length; i++)

            {

                data = new Attachment(path[i], MediaTypeNames.Application.Octet);//实例化附件

                disposition = data.ContentDisposition;

                disposition.CreationDate = System.IO.File.GetCreationTime(path[i]);//获取 附件的创建日期

                disposition.ModificationDate = System.IO.File.GetLastWriteTime(path[i]);//获取附件的修改日期

                disposition.ReadDate = System.IO.File.GetLastAccessTime(path[i]);//获取附 件的读取日期

                mailMessage.Attachments.Add(data);//添加到附件中

            }

        }

        /// <summary>

        /// 异步发送邮件

        /// </summary>

        /// <param name="CompletedMethod"></param>

        public void SendAsync(SendCompletedEventHandler CompletedMethod)

        {

            if (mailMessage != null)

            {

                smtpClient = new SmtpClient();

                smtpClient.Credentials = new System.Net.NetworkCredential

                (mailMessage.From.Address, password);//设置发件人身份的票据

                smtpClient.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network;

                smtpClient.Host = "smtp." + mailMessage.From.Host;

                smtpClient.SendCompleted += new SendCompletedEventHandler

                (CompletedMethod);//注册异步发送邮件完成时的事件

                smtpClient.SendAsync(mailMessage, mailMessage.Body);

            }

        }

        /// <summary>

        /// 发送邮件

        /// </summary>

        public void Send()

        {

            if (mailMessage != null)

            {

                try

                {

                    smtpClient = new SmtpClient();

                    smtpClient.Credentials = new System.Net.NetworkCredential

                    (mailMessage.From.Address, password);//设置发件人身份的票据

                    smtpClient.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network;

                    smtpClient.Host = "smtp." + mailMessage.From.Host;

                    smtpClient.Timeout = ;　／／设置超时时间

                    smtpClient.Send(mailMessage);

                }

                catch (SmtpException ex)

                {

                      Info = "邮件发送失败";

                }

            }

        }

        private static void CompletedMethod(object sender, System.ComponentModel.AsyncCompletedEventArgs e)

        {

            // Get the unique identifier for this asynchronous operation.

            String token = (string)e.UserState;

            if (e.Error != null)

            {

                // 异步发送的错误信息

                // Console.WriteLine("[{0}] {1}", token, e.Error.ToString());

            }

        }

    }

　２.使用，经测试ＱＱ／１６３／ｓｉｎａ均可使用

　　

　　 TYKY_OA.Web.CSendMail sm = new CSendMail(this.qqNum.Value.Trim() + "@qq.com",
    "ＸＸＸ@163.com", "已重置你的的密码，新密码为：" + password + "  请注意保管！",
    "密码重置邮件", "××××××");

     sm.Send();

     //发送失败

     if (sm.Info != null)

     {

         ClientScript.RegisterStartupScript(this.GetType(), "tooltip", "alert('邮件发送失败，可能的原因是网络故障或邮箱不可达...')",true);

     }

     //发送成功

     else

     {

        //修改数据库密码字段

        staff.pwd = password;

        if (bllstaffs.Update(staff))

        {

             ClientScript.RegisterStartupScript(this.GetType(), "tooltip", "alert('密码已重置，请注意查收邮件')", true);

        }

       else

        {

             ClientScript.RegisterStartupScript(this.GetType(), "tooltip", "alert('密码重置失败)", true);

        }

}