我搜索网络并找到了解决方案,这个链接解决了我的问题。这是一些用户完整的代码,我需要提供 CreateAlternateViewFromString。
MailMessage emailmsg = new MailMessage("from@address.co.za", "to@address.co.za")
emailmsg.Subject = "Subject";
emailmsg.IsBodyHtml = false;
emailmsg.ReplyToList.Add("from@address.co.za");
emailmsg.BodyEncoding = System.Text.Encoding.UTF8;
emailmsg.HeadersEncoding = System.Text.Encoding.UTF8;
emailmsg.SubjectEncoding = System.Text.Encoding.UTF8;
emailmsg.Body = null;
var plainView = AlternateView.CreateAlternateViewFromString(EmailBody, emailmsg.BodyEncoding, "text/plain");
plainView.TransferEncoding = TransferEncoding.SevenBit;
emailmsg.AlternateViews.Add(plainView);
SmtpClient sSmtp = new SmtpClient();
sSmtp.Send(emailmsg);