C#发送邮件

public class MailUtil
    {

        public SmtpClient smtpClient = null;// 设置smtp协议
        public MailMessage mailMessage_mai = null; //设置邮件信息,要发送的内容

        #region 发邮件
        /// <summary>
        /// 发邮件
        /// </summary>
        /// <param name="smtp">邮箱服务器名称</param>
        /// <param name="affix">附件路径</param>
        /// <param name="from">发件箱地址</param>
        /// <param name="pwd">发件箱密码</param>
        /// <param name="to">收件箱地址</param>
        /// <param name="title">邮件标题</param>
        /// <param name="body">邮件正文</param>
        /// <returns></returns>
        public bool SendMail(string smtp,string affix,
            string from ,string pwd,string to,string title,string body)
        {
            smtpClient = new SmtpClient();
            smtpClient .Host = smtp;
            smtpClient.UseDefaultCredentials = false;

            //指定服务器认证
            NetworkCredential network = new NetworkCredential(from,pwd);

            //指定发件人信息,包括邮箱地址和密码
            smtpClient.Credentials = new NetworkCredential(from,pwd);
            //指定如何发送邮件
            smtpClient.DeliveryMethod = SmtpDeliveryMethod.Network;
          

            //创建mailMessage对象
            mailMessage_mai = new MailMessage(from,to);
            mailMessage_mai.Subject = title;

            //设置正文默认格式为html
            mailMessage_mai.Body = body;
            mailMessage_mai.IsBodyHtml = true;
            mailMessage_mai.BodyEncoding = Encoding.UTF8;

            //添加附件
            if (!string.IsNullOrEmpty(affix))
            {
                Attachment data = new Attachment(affix,MediaTypeNames.Application.Octet);
                mailMessage_mai.Attachments.Add(data);
            }

            try
            {
                //smtpClient.Send(mailMessage_mai);
                //发送
                smtpClient.SendAsync(mailMessage_mai,"000000000");

                return true;//返回true则发送成功
            }
            catch (Exception)
            {
                return false;//返回false则发送失败
            }
        }
        #endregion

    }