c#中郵件收發處理（POP3,IMAP,SMTP）

                return content;

            }

            catch (Exception err)
            {
                Log(err.Message);
                return "Error";
            }
        }
        public void DeleteMail(int id)
        {
            _data = "DELE" + id + _CRLF;
            _charData = System.Text.Encoding.ASCII.GetBytes(_data.ToCharArray());
            _netStream.Write(_charData, 0, _charData.Length);
            if (!CheckResult(_reader.ReadLine()))
              &n throw new Exception("Delete Error");

        }
        /// <summary>
        /// close connection
        /// </summary>
        public void Close()
        {

            _data = "QUIT" + _CRLF;
            _charData = System.Text.Encoding.ASCII.GetBytes(_data.ToCharArray());
            _netStream.Write(_charData, 0, _charData.Length);

            //close
            _netStream.Close();
            _reader.Close();
        }

        private bool CheckResult(string reply)
        {
            Log(reply);
            if (reply.IndexOf("+OK") > -1)
                return true;
            else
                return false;
        }
        private void Log(string msg)
        {
            _log += msg + "\r\n";
        }
    }
。。。。。
但是這種方式的一個問題就是關於解析信件的格式。如果是附件的話，他也直接給出了二進制，不容易使用。
所以，可以使用一個現成的工具：LumiSoft.Net.POP3.ClIEnt。這裡面已經給寫好了實現，用起來也很簡單。
這是一個簡單的用法（這裡使用了兩種處理方式，前一種是不建議使用的）
。。
            using (POP3_Client pop3 = new POP3_ClIEnt())
            {
                //與Pop3服務器建立連接
  ;             pop3.Connect(_popServer, _pop3port,false);
                //驗證身份
                pop3.Authenticate(_user, _pwd, false);

                //get all messages
                POP3_MessagesInfo infos = pop3.GetMessagesInfo();
                 foreach (POP3_MessageInfo info in infos)
                {
                    byte[] bytes = pop3.GetMessage(info.MessageNumber);
                    Mime mime = Mime.Parse(bytes);
                    HandleMail(mime);
                    //delete it at last
                    //pop3.DeleteMessage(info.MessageNumber);
                }
                //the second way to do it
//for (int i = 0; i < pop3.Messages.Count; i++)
                //{
                //    byte[] bytes = pop3.Messages[i].MessageToByte();
                //    Mime mime = Mime.Parse(bytes);
                //    HandleMail(mime);
                //    //delete it at last
                //    //pop3.DeleteMessage(pop3.Messages[i].SequenceNumber);
           。。。
取得的郵件可以這要給獲得。
   #region pop3
            //string customer = mime.MainEntity.To.ToAddressListString();//cargo company
            //string sender = mime.MainEntity.From.ToAddressListString();//this is customer who send

            #endregion
            string customer = MailboxesToString(envelope.To);//cargo company
            string sender = MailboxesToString(envelope.From);//this is customer who send

。。。
除此之外，它提供的另外一個工具是IMAP，它操作起來更加方便。代碼如下：
。
  IMAP_Client clnt = new IMAP_ClIEnt();
            try
            {
                clnt.Connect("mail.xx.com", 143, false);
                clnt.Authenticate("user", "passWord");
                string[] folders = clnt.GetFolders();//get all types

                string folder = "Inbox";
                clnt.SelectFolder(folder);
                IMAP_SequenceSet sequence_set = new IMAP_SequenceSet();
                // All messages
                sequence_set.Parse(string.Format("{0}:{1}", 1, clnt.MessagesCount));

                IMAP_FetchItem[] fetchItems = clnt.FetchMessages(
                        sequence_set,
                        IMAP_FetchItem_Flags.UID | IMAP_FetchItem_Flags.MessageFlags | IMAP_FetchItem_Flags.Size | IMAP_FetchItem_Flags.Envelope,
                        true, false
                        );
                //int count =0;
                foreach (IMAP_FetchItem fetchItem in fetchItems)
                {
                    IMAP_Envelope envelope = fetchItem.Envelope;
                    //hanldle it, means read and search and reply
                    try
                    {
        &nbsp;               HandleMail(envelope);
                        //count++;
                    }
                    catch (Exception ex)
                    {
                        Log("Sys", ex.Message);
                    }
                }
                //delete it after hanlde
                clnt.DeleteMessages(sequence_set, false);
                //disconnect
                clnt.Disconnect();

      &nb       //MessageBox.Show(count.ToString() + " of " + fetchItems .Length+ " Success");
            }
            catch (Exception x)
            {
                Log("Sys", x.Message);
                //MessageBox.Show(x.Message);
            }
 
。。

        /// <summary>
        /// need passWord,username, smtpserver
        /// </summary>
        /// <param name="to"></param>
        /// <param name="subject"></param>
        /// <param name="body"></param>
        static public void SendMail(string sendTo, string subject, string body)
        {
            //.Net smtp
            System.Web.Mail.MailMessage mailmsg = new System.Web.Mail.MailMessage();
            mailmsg.To = sendTo;
            //mailmsg.Cc = cc;
            mailmsg.Subject = subject;
            mailmsg.Body = body;

            //sender here
            mailmsg.From = EMail.accountName;
            // certify needed 
            mailmsg.FIElds.Add("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate", "1");//1 is to certify
            //the user id  
            mailmsg.FIElds.Add(
                "http://schemas.microsoft.com/cdo/configuration/sendusername",
                EMail.accountName);
             //the passWord
            mailmsg.FIElds.Add(
                "http://schemas.microsoft.com/cdo/configuration/sendpassWord",
                 EMail.passWord);

            System.Web.Mail.SmtpMail.SmtpServer = EMail.smtpServer;
            System.Web.Mail.SmtpMail.Send(mailmsg);

        }

        #region send mail2
        /// <summary>
        /// need username,smtp,smtp port
        /// </summary>
        /// <param name="sendTo"></param>
        /// <param name="subject"></param>
        /// <param name="body"></param>
        static public void SendMail2(string sendTo,string subject, string body)
  &nbs   {
            System.Net.Mail.MailMessage msg = new System.Net.Mail.MailMessage();
            msg.To.Add(sendTo);
            msg.From = new System.Net.Mail.MailAddress(accountName );