C# 设置发送邮件的Deliverynotification和Readnotification

我向客户发送发票和警告/提醒，现在这些邮件应该标记为Deliverynotification和Readnotification。因此，我知道客户何时收到并阅读发票

MailMessage email = new MailMessage();
email.Priority = MailPriority.Normal;
email.DeliveryNotificationOptions = DeliveryNotificationOptions.OnSuccess; // Deliverynotification? 
email.Attachments.Add(new Attachment(docDunPath));
email.Attachments.Add(new Attachment(docInvoicePath));
email.Subject = "-----------";
email.IsBodyHtml = true;                
email.Body = MailText;

到目前为止一切正常，我只想设置收件人阅读邮件后自动回复的选项。因此，我可以肯定他看到了他的发票。

因此，在意识到我使用了System.Net.Mail之后，我切换到了Microsoft.Exchange.WebServices，现在它运行得非常好

EmailMessage email = new EmailMessage(service);              
email.IsDeliveryReceiptRequested = true;                          
email.IsReadReceiptRequested = true;