使用“名称”属性时，SmtpClient 发送的附件顺序不正确

本文关键字：不正确 顺序 SmtpClient 名称 属性 使用 | 更新日期: 2023-09-27 18:30:39

任何人都可以重现此问题吗？在我看来，这是SmtpClient（.NET 4.0）中一个非常严重的错误，但我不敢相信以前没有人见过这个，谷歌似乎没有向任何人展示类似的问题。

当发送包含 1 个以上附件的电子邮件并使用"Attachment.Name"属性时，附件的名称将不正确（例如，2 个附件的名称将交换）。解决方法（实际上可能是要设置的正确属性）是使用 ContentDisposition.FileName。但如果每个人都发生这种情况，我会非常感兴趣。任何人都可以重现此问题吗？在我看来，这是SmtpClient（.NET 4.0）中一个非常严重的错误，但我不敢相信以前没有人见过这个，谷歌似乎没有向任何人展示类似的问题。您需要在 c：''tmp''emailin'' 中创建几个 zip 文件

var zipCt = new ContentType { MediaType = MediaTypeNames.Application.Zip };
var attachmentA = new Attachment(@"c:'tmp'emailin'a.zip", zipCt);
attachmentA.ContentDisposition.FileName = "a.zip";
attachmentA.Name = "a.zip";
var attachmentB = new Attachment(@"c:'tmp'emailin'b.zip", zipCt);
attachmentB.ContentDisposition.FileName = "b.zip";
attachmentB.Name = "b.zip";
var msg = new MailMessage("testfrom@example.com", "testto@example.com")
{
       Body = "body",
       Subject = "subject"
};
msg.Attachments.Add(attachmentA);
msg.Attachments.Add(attachmentB);
using (var smtp = new SmtpClient())
{
     smtp.DeliveryMethod = SmtpDeliveryMethod.SpecifiedPickupDirectory;
     smtp.PickupDirectoryLocation = @"c:'tmp'emailout'";
     smtp.Send(msg);
}

如果你现在查看 c：''tmp''emailout'' 中的 eml 文件，你会看到类似

X-Sender: testfrom@example.com
X-Receiver: testto@example.com
MIME-Version: 1.0
From: testfrom@example.com
To: testto@example.com
Date: 11 Apr 2012 12:36:48 +0100
Subject: subject
Content-Type: multipart/mixed; boundary=--boundary_0_1b7bb1ee-ba28-4258-b662-554adb7ff81a

----boundary_0_1b7bb1ee-ba28-4258-b662-554adb7ff81a
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: quoted-printable
body
----boundary_0_1b7bb1ee-ba28-4258-b662-554adb7ff81a
Content-Type: application/zip; name=b.zip
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename=a.zip
UEsDBAoAAAAAAG5ki0AAAAAAAAAAAAAAAAAFAAAAYS50eHRQSwECPwAKAAAAAABu
ZItAAAAAAAAAAAAAAAAABQAkAAAAAAAAACAAAAAAAAAAYS50eHQKACAAAAAAAAEA
GADa2JQw1xfNAdrYlDDXF80B2tiUMNcXzQFQSwUGAAAAAAEAAQBXAAAAIwAAAAAA
----boundary_0_1b7bb1ee-ba28-4258-b662-554adb7ff81a
Content-Type: application/zip; name=a.zip
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename=b.zip
UEsDBAoAAAAAAHZki0AAAAAAAAAAAAAAAAAFAAAAYi50eHRQSwECPwAKAAAAAAB2
ZItAAAAAAAAAAAAAAAAABQAkAAAAAAAAACAAAAAAAAAAYi50eHQKACAAAAAAAAEA
GAD67/k51xfNAfrv+TnXF80B2tiUMNcXzQFQSwUGAAAAAAEAAQBXAAAAIwAAAAAA
----boundary_0_1b7bb1ee-ba28-4258-b662-554adb7ff81a--

请注意，内容类型：和内容处置：文件名如何与每个附件不匹配。

我做错了什么吗？这是我应该用MS记录的错误吗？

使用“名称”属性时，SmtpClient 发送的附件顺序不正确

这是因为每个附件都需要一个新的 ContentType 实例。

var zipCt = new ContentType { MediaType = MediaTypeNames.Application.Zip };
var zipCt2 = new ContentType { MediaType = MediaTypeNames.Application.Zip };
var attachmentA = new Attachment(@"c:'tmp'emailin'a.zip", zipCt);
attachmentA.ContentDisposition.FileName = "a.zip";
attachmentA.Name = "a.zip";
var attachmentB = new Attachment(@"c:'tmp'emailin'b.zip", zipCt2);
attachmentB.ContentDisposition.FileName = "b.zip";
attachmentB.Name = "b.zip";

应该解决您的问题。

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