/// <summary>
 /// Adds an custom header to the MailMessage.
 ///	NOTE: some SMTP servers will reject improper custom headers
 ///</summary>
 /// <param name="mailheader">MailHeader instance</param>
 /// <example>
 /// <code>
 ///     MailMessage msg = new MailMessage("*****@*****.**", "*****@*****.**");
 ///		MailHeader header = new MailHeader("X-Something", "HeaderValue");
 ///		msg.AddCustomHeader(header);
 /// </code>
 /// </example>
 public void AddCustomHeader(MailHeader mailheader)
 {
     if (mailheader.name != null && mailheader.body != null)
     {
         customHeaders.Add(mailheader);
     }
 }
        /// <summary>Returns the MailMessage as a RFC 822 formatted message</summary>
        public override string ToString()
        {
            StringBuilder sb = new StringBuilder(60000);

            sb.Append("Reply-To: " + ReplyTo.ToMessageHeaderString(charset));
            sb.Append(SmtpConstants.CrLf);
            sb.Append("From: " + From.ToMessageHeaderString(charset));
            sb.Append(SmtpConstants.CrLf);

            if (1 == 2)
            {
                if (Stringer.IsNotEmpty(ReplyTo.FriendlyName))
                {
                    string rt = MessageHeaderString.EncodeAsRequired(
                        Stringer.Enquote(ReplyTo.FriendlyName, '"', QuoteEncapsulation.Escape),
                        new QuotedPrintableTraits( ));
                    sb.Append("Reply-To: ");
                    sb.Append(rt);
                    sb.Append(" <" + ReplyTo.Address + ">" + SmtpConstants.CrLf);
                    string debug = sb.ToString( );
                }
                else
                {
                    sb.Append("Reply-To: <" + ReplyTo.Address + ">" + SmtpConstants.CrLf);
                }

                // from email address.
                if (Stringer.IsNotEmpty(From.FriendlyName))
                {
                    string rt = MessageHeaderString.EncodeAsRequired(
                        Stringer.Enquote(From.FriendlyName, '"', QuoteEncapsulation.Escape),
                        new QuotedPrintableTraits( ));
                    sb.Append("From: ");
                    sb.Append(rt);
                    sb.Append(" <" + From.Address + ">" + SmtpConstants.CrLf);
                }
                else
                {
                    sb.Append("From: <" + From.Address + ">" + SmtpConstants.CrLf);
                }
            }

            sb.Append("To: " + CreateAddressList(mToRecipients) + "\r\n");

            if (CCRecipients.Count != 0)
            {
                sb.Append("CC: " + CreateAddressList(CCRecipients) + "\r\n");
            }

            if (subject != null && subject.Length > 0)
            {
                StringBuilder cleanSubject = new StringBuilder(subject);
                cleanSubject.Replace("\r\n", null);
                cleanSubject.Replace("\n", null);

                sb.Append("Subject: " + MailEncoder.ConvertHeaderToQP(cleanSubject.ToString(), charset) + "\r\n");
            }

            sb.Append("Date: " + DateTime.Now.ToUniversalTime().ToString("R") + "\r\n");
            sb.Append(SmtpConfig.X_MAILER_HEADER + "\r\n");

            if (notification)
            {
                if (ReplyTo.FriendlyName != null && ReplyTo.FriendlyName.Length != 0)
                {
                    sb.Append("Disposition-Notification-To: " + MailEncoder.ConvertHeaderToQP(ReplyTo.FriendlyName, charset) + " <" + ReplyTo.Address + ">\r\n");
                }
                else
                {
                    sb.Append("Disposition-Notification-To: <" + ReplyTo.Address + ">\r\n");
                }
            }

            if (priority != null)
            {
                sb.Append("X-Priority: " + priority + "\r\n");
            }

            if (customHeaders != null)
            {
                for (IEnumerator i = customHeaders.GetEnumerator(); i.MoveNext();)
                {
                    MailHeader m = (MailHeader)i.Current;

                    if (m.name.Length >= 0 && m.body.Length >= 0)
                    {
                        sb.Append(m.name + ":" + MailEncoder.ConvertHeaderToQP(m.body, charset) + "\r\n");
                    }
                    else
                    {
                        // TODO: Check if below is within RFC spec.
                        sb.Append(m.name + ":\r\n");
                    }
                }
            }

            sb.Append("MIME-Version: 1.0\r\n");
            sb.Append(GetMessageBody());

            return(sb.ToString());
        }