記憶所及之處

//讀取回條

MailMessage msg = new MailMessage("Send@gmail", email, subject, msgbody);

msg.Headers.Add("Disposition-Notification-To", "<To@gmail>");

//送達回條

msg.DeliveryNotificationOptions = DeliveryNotificationOptions.OnSuccess;

SmtpClient MailClient = new SmtpClient();

MailClient.DeliveryMethod = SmtpDeliveryMethod.Network;