Question

是否有人能够发送带附件的电子邮件，其中附件保存为utf8编码。我试过但是当我在记事本中打开它时，它说编码是ascii。注意：我不想先保存文件。

// Init the smtp client and set the network credentials
            SmtpClient smtpClient = new SmtpClient();
            smtpClient.Host = getParameters("MailBoxHost");

            // Create MailMessage
            MailMessage message = new MailMessage("team@ccccc.co.nz",toAddress,subject, body);

            using (MemoryStream memoryStream = new MemoryStream())
            {
                byte[] contentAsBytes = Encoding.UTF8.GetBytes(attachment);
                memoryStream.Write(contentAsBytes, 0, contentAsBytes.Length);

                // Set the position to the beginning of the stream.
                memoryStream.Seek(0, SeekOrigin.Begin);

                // Create attachment
                ContentType contentType = new ContentType();
                contentType.Name = attachementname;
                contentType.CharSet = "UTF-8";

                System.Text.Encoding inputEnc = System.Text.Encoding.UTF8;

               Attachment attFile = new Attachment(memoryStream, contentType);

                // Add the attachment
                message.Attachments.Add(attFile);

                // Send Mail via SmtpClient
                smtpClient.Send(message);


            }

Answer 1

在流的开头添加UTF-8的BOM (byte order mark)：

0xEF,0xBB,0xBF

代码：

byte[] bom = { 0xEF, 0xBB, 0xBF };
memoryStream.Write(bom, 0, bom.Length);

byte[] contentAsBytes = Encoding.UTF8.GetBytes(attachment);
memoryStream.Write(contentAsBytes, 0, contentAsBytes.Length);

Answer 2

假设您的附件是文字，ContentType类的默认构造函数会将附件的Content-Type标题设置为application/octet-stream，但需要将其设置为text/plain ，例如：

ContentType contentType = new ContentType(MediaTypeNames.Text.Plain);

或者：

ContentType contentType = new ContentType(); 
contentType.MediaType = MediaTypeNames.Text.Plain;

此外，您应为附件指定TransferEncoding，因为UTF-8不是7位清洁（许多电子邮件系统仍然需要），例如：

attFile.TransferEncoding = TransferEncoding.QuotedPrintable;

或者：

attFile.TransferEncoding = TransferEncoding.Base64;

电子邮件中的附件以使用UTF-8编码保存

2 个答案: