C# 发送邮件中包含图片

            List<string> To = new List<string>();
            To.Add("jake_ge@askey.com.tw");
            List<string> CC = new List<string>();
            CC.Add("jake_ge@askey.com.tw");
            MailMessage Message = new MailMessage();
            Message.IsBodyHtml = true;
            Message.BodyEncoding = UTF8Encoding.UTF8;
            Message.SubjectEncoding = UTF8Encoding.UTF8;
            Message.Priority = MailPriority.Normal;
            Message.Sender = new MailAddress("b2b@askey.com.tw");
            Message.Subject = "Test";
            Message.From = new MailAddress("b2b@askey.com.tw");
            for (int i = 0; i < To.Count; i++)
            {
                Message.To.Add(new MailAddress(To[i]));
            }
            for (int i = 0; i < CC.Count; i++)
            {
                Message.CC.Add(new MailAddress(CC[i]));
            }
            Message.Body = GenMailBody();
            //添加附件
            Message.Attachments.Add(new Attachment("C:\\aa.jpg"));
            //设置附件类型
            Message.Attachments[0].ContentType.Name = "image/jpg";
            //设置附件 Id
            Message.Attachments[0].ContentId = "ewen";
            //设置附件为 inline-内联
            Message.Attachments[0].ContentDisposition.Inline = true;
            //设置附件的编码格式
            Message.Attachments[0].TransferEncoding = System.Net.Mime.TransferEncoding.Base64;
            SmtpClient client = new SmtpClient();
            client.Host = "smtp.local";
            client.DeliveryMethod = SmtpDeliveryMethod.Network;
            bool IsSend = false;
            try
            {
                client.Send(Message);
            }
            catch (Exception e1)
            {
                //MailLog(To, To, e1.Message.ToString());
            }

主要是

Message.Attachments[0].ContentId = "ewen"
中设置的id要和mail body中img标签中的src要对应起来

        public static string GenMailBody()
        {
            StringBuilder sb = new StringBuilder();
            sb.Append("Dear Suppliers：<br/>");
            sb.Append("近期Askey頻發亞旭進料標籤異常，主要因標籤Serial ID的編碼重複造成Askey不能上線，特此郵件通知各Suppliers特別注意此項！<br/>");
            sb.Append("如有任何疑問請E-Mail寄送至Huiqin_zhang@askey.com.tw, sqe_team@askey.com.tw<br/>");
            sb.Append("<img alt='' src=cid:ewen>");
            return sb.ToString();
        }