关于邮件群发有关问题

    public class MailInfo    {        private String _sanderAddress;        private String _sanderName;        private String _sanderPwd;        private List<String> _recieverAddress;        private String _mailSubject;        private String _mailBody;        private Attachment _mailAttachment;        /// <summary>        /// 附件        /// </summary>        public Attachment MailAttachment        {            get { return _mailAttachment; }            set { _mailAttachment = value; }        }        /// <summary>        /// 邮件主体        /// </summary>        public String MailBody        {            get { return _mailBody; }            set { _mailBody = value; }        }        /// <summary>        /// 邮件标题        /// </summary>        public String MailSubject        {            get { return _mailSubject; }            set { _mailSubject = value; }        }        /// <summary>        /// 接收者地址        /// </summary>        public List<String> RecieverAddress        {            get { return _recieverAddress; }            set { _recieverAddress = value; }        }        /// <summary>        /// 发送者密码        /// </summary>        public String SanderPwd        {            get { return _sanderPwd; }            set { _sanderPwd = value; }        }        /// <summary>        /// 发送者名称        /// </summary>        public String SanderName        {            get { return _sanderName; }            set { _sanderName = value; }        }        /// <summary>        /// 发送者地址        /// </summary>        public String SanderAddress        {            get { return _sanderAddress; }            set { _sanderAddress = value; }        }    }

protected static void sendMail(Object obj)        {            MailInfo mi = (MailInfo)obj;            for (int i = 0; i < mi.RecieverAddress.Count; i++)            {                MailMessage msg = new MailMessage();                msg.To.Add(new MailAddress(mi.RecieverAddress[i]));                msg.From = new MailAddress(mi.SanderAddress);                msg.Subject = mi.MailSubject;                msg.Body = mi.MailBody;                msg.BodyEncoding = System.Text.Encoding.UTF8;                msg.SubjectEncoding = System.Text.Encoding.UTF8;                msg.IsBodyHtml = false;                msg.Priority = MailPriority.High;                if (mi.MailAttachment != null)                { msg.Attachments.Add(mi.MailAttachment); }                SmtpClient client = new SmtpClient();                client.Host = "smtp.sina.com.cn";                client.UseDefaultCredentials = false;                NetworkCredential basicAuthenticationInfo = new NetworkCredential(mi.SanderName, mi.SanderPwd);                client.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network;                client.Credentials = basicAuthenticationInfo;                try                { client.Send(msg); }                catch (Exception ex)                { Console.WriteLine(ex.Message); }            }        }