c# 邮件发送

1     <!--SMTP server address-->
2     <add key="SmtpServer" value="mail.anroc.com.au" />
3     <add key="SmtpDeaultEmail" value="Test@anroc.com.au" />
4     <!--email address and password used to send mails-->
5     <add key="FromUser" value="" />
6     <add key="FromPwd" value="" />

 private static readonly string _smtpServer = ConfigurationManager.AppSettings["SmtpServer"];
 private static readonly string _userAccount = ConfigurationManager.AppSettings["FromUser"];
 private static readonly string _userPwd = ConfigurationManager.AppSettings["FromPwd"];
 private static readonly string _toUser = ConfigurationManager.AppSettings["ToUser"];
 private static readonly string _defaultEmailAddress = ConfigurationManager.AppSettings["SmtpDeaultEmail"];

public static Operate SendEmail(string title, string content, string toUserEmail = "", string filepath = "")
        {
            var result=new Operate();
            try
            {
　　　　　　　　　　//邮件接收人
                var sendTo = toUserEmail == "" ? _toUser : toUserEmail;
　　　　　　　　　　
                var client = new SmtpClient(_smtpServer);
                client.Timeout = 60000;
                client.UseDefaultCredentials = false;
                client.Credentials = new System.Net.NetworkCredential(_userAccount, _userPwd);
                client.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network;
                var message = new MailMessage();
                if (filepath != "")
                {
                    var attach = new Attachment(filepath);
                    attach.Name = Path.GetFileName(filepath);
                    attach.NameEncoding = Encoding.GetEncoding("gb2312");
                    attach.TransferEncoding = System.Net.Mime.TransferEncoding.Base64;
                    attach.ContentDisposition.Inline = true;
                    attach.ContentDisposition.DispositionType = System.Net.Mime.DispositionTypeNames.Inline;
                    message.Attachments.Add(attach);
                }
                message.SubjectEncoding = System.Text.Encoding.UTF8;
                message.BodyEncoding = System.Text.Encoding.UTF8;
                message.From = new System.Net.Mail.MailAddress(_defaultEmailAddress);
                message.To.Add(new System.Net.Mail.MailAddress(sendTo));
                message.IsBodyHtml = true;
                message.Subject = title.Replace("\r", "").Replace("\n", "").Trim();
                message.Body = content;
                client.SendMailAsync(message);
                result.Status = 1;
            }
            catch (Exception ex)
            {
                result.Status = -1;
                result.Message = ex.Message;
                Logger.WriteErrorLog(ex);
            }
            return result;
        }