从内存流发送带有附件的 MailKit 电子邮件

Question

如何使用 MailKit 从内存流发送带有附件的电子邮件？目前，我正在使用常规 SMTP 发送并使用以下代码附加文件，但找不到任何正确的示例来使用 MailKit 包发送它。我已经阅读了这两篇文档，但找不到合适的解决方案。 http://www.mimekit.net/docs/html/M_MimeKit_AttachmentCollection_Add_6.htm

using System.Net.Mail;
MemoryStream memoryStream = new MemoryStream(bytes);
                    message.Attachments.Add(new Attachment(memoryStream, "Receipt.pdf", MediaTypeNames.Application.Pdf));

这是我的 MailKit 电子邮件代码：

#region MailKit
                string fromEmail = GlobalVariable.FromEmail;
                string fromEmailPwd = "";//add sender password
                var email = new MimeKit.MimeMessage();
                email.From.Add(new MimeKit.MailboxAddress("Sender", fromEmail));

                email.To.Add(new MimeKit.MailboxAddress("receiver", "receiver@gmail.com"));
                var emailBody = new MimeKit.BodyBuilder
                {
                    HtmlBody = htmlString
                };
                email.Subject = "test Booking";
                email.Body = emailBody.ToMessageBody();
                //bytes is parameter.
                //MemoryStream memoryStream = new MemoryStream(bytes);
                //message.Attachments.Add(new Attachment(memoryStream, "Receipt.pdf", MediaTypeNames.Application.Pdf));

                using (var smtp = new MailKit.Net.Smtp.SmtpClient())
                {
                    smtp.Connect("smtp.gmail.com", 465, true);
                    smtp.Authenticate(fromEmail, fromEmailPwd);
                    smtp.Send(email);
                    smtp.Disconnect(true);
                }
                #endregion

Answer 1

如果您想坚持使用 MimeKit 的 BodyBuilder 来构建消息正文，您可以执行以下操作：

var emailBody = new MimeKit.BodyBuilder
{
    HtmlBody = htmlString
};
emailBody.Attachments.Add ("Receipt.pdf", bytes);

// If you find that MimeKit does not properly auto-detect the mime-type based on the
// filename, you can specify a mime-type like this:
//emailBody.Attachments.Add ("Receipt.pdf", bytes, ContentType.Parse (MediaTypeNames.Application.Pdf));

message.Body = emailBody.ToMessageBody ();

Answer 2

它是这样完成的：您需要TextPart为字符串内容创建 a ，MimePart为附件创建 a ，并将两者添加到 a中Multipart，这是BodyMimeMessage

我假设您想要发送一个 HTML 字符串textContent和一个名称为 的 PDF 文件filename，该文件已使用任何名为 的流读取stream。

var multipart = new Multipart("mixed");
var textPart = new TextPart(TextFormat.Html)
{
    Text = textContent,
    ContentTransferEncoding = ContentEncoding.Base64,
};
multipart.Add(textPart);

stream.Position = 0; // you MUST reset stream position

var attachmentPart = new MimePart(MediaTypeNames.Application.Pdf)
{
    Content = new MimeContent(stream),
    ContentId = filename,
    ContentTransferEncoding = ContentEncoding.Base64,
    FileName = filename
};
multipart.Add(attachmentPart);

mimeMessage.Body = multipart;

请注意，对于contentType我使用的MediaTypeNames.Application.PdfDLLSystem.Net.Mail和命名空间System.Net.Mime，它等于字符串"application/pdf"。您可以使用您喜欢的任何其他库，或者编写自己的库。