Question

我们遇到了发送包含长名称和重音符号附件的电子邮件的问题。

尺寸或类型似乎不影响结果（我尝试使用txt＆amp; pdf，300kb和3833kb的尺寸）

经过一番搜索，我发现这篇文章http://social.msdn.microsoft.com/Forums/en-US/dotnetframeworkde/thread/b6c764f7-4697-4394-b45f-128a24306d55展示了如何解决这个问题。

如果我的名字很长（参见attachement2变量名），它会起作用。但是如果名称略短（参见attachment1变量名称），则名称为 - = _ iso-8859-1_Q_Example，_Example_and_other _

我认为它与SplitEncodedAttachmentName中的以下某行有关 encodedAttachmentName = encodedAttachmentName.Remove（encodedAttachmentName.Length - encodingtoken.Length，encodingtoken.Length）;

这是对vars的观察 attach1 - “=？ISO-8859-1？Q？示例= 2c_Example_and_other_Repr = e9senta.txt？=”

attach2 - “=？ISO-8859-1？Q？示例= 2c_Example_and_other_Repr = e9sentant_Example_Examp？==？ISO-8859-1？Q？le_Example_Example_Example_Example2.txt？=”

我似乎无法正确发送附件1.

（我过去回答过这个问题 - MailMessage Attachment filename with accents但是我有一个错误，重构并遇到了这个问题..）

这是我可能出现的导致错误的最小代码示例。

class Program
{
    static void Main(string[] args)
    {
        Attachment attachment = new Attachment(@"c:\client\temp\Example,_Example_and_other_Représenta.pdf"); //3488kb
        Attachment attachment2 = new Attachment(@"c:\client\temp\Example,_Example_and_other_Représentant_Example_Example_Example_Example_Example_Example.pdf"); //3488kb

        Console.WriteLine(attachment.Name);

        MailMessage mm = new MailMessage();
         mm.From = new MailAddress("toemail");
         mm.To.Add("toemail");
        mm.Subject = "Yo";
        mm.Body = "hello";
        mm.Attachments.Add(CreateAttachment(attachment, attachment.Name)); // =_iso-8859-1_Q_Example,_Example_and_other_
        mm.Attachments.Add(CreateAttachment(attachment2, attachment2.Name));

        SmtpClient smtp = new SmtpClient("SmptServer");
        smtp.Send(mm);
    }

    /// <summary>
    /// This method fixes the name of the attachment to allow accents
    /// </summary>
    /// <remarks>Taken from http://social.msdn.microsoft.com/Forums/en-US/dotnetframeworkde/thread/b6c764f7-4697-4394-b45f-128a24306d55</remarks>
    public static Attachment CreateAttachment(Attachment attachmentFile, string displayName)
    {
        Attachment attachment = attachmentFile;
        attachment.TransferEncoding = TransferEncoding.Base64;

        string tranferEncodingMarker = "Q";
        string encodingMarker = "ISO-8859-1";
        int maxChunkLength = 76;

        attachment.NameEncoding = Encoding.GetEncoding(encodingMarker);

        string encodingtoken = String.Format("=?{0}?{1}?", encodingMarker, tranferEncodingMarker);
        string softbreak = "?=";
        string encodedAttachmentName = encodingtoken;
        encodedAttachmentName = HttpUtility.UrlEncode(displayName, Encoding.Default).Replace("+", " ").Replace("%", "=");

        encodedAttachmentName = SplitEncodedAttachmentName(encodingtoken, softbreak, maxChunkLength, encodedAttachmentName);
        attachment.Name = encodedAttachmentName;

        return attachment;
    }


    private static IEnumerable<string> SplitByLength(string stringToSplit, int length)
    {
        while (stringToSplit.Length > length)
        {
            yield return stringToSplit.Substring(0, length);
            stringToSplit = stringToSplit.Substring(length);
        }

        if (stringToSplit.Length > 0)
        {
            yield return stringToSplit;
        }
    }

    private static string SplitEncodedAttachmentName(string encodingtoken, string softbreak, int maxChunkLength, string encoded)
    {
        int splitLength = maxChunkLength - encodingtoken.Length - (softbreak.Length * 2);
        var parts = SplitByLength(encoded, splitLength);

        string encodedAttachmentName = encodingtoken;

        foreach (var part in parts)
        {
            encodedAttachmentName += part + softbreak + encodingtoken;
        }

        encodedAttachmentName = encodedAttachmentName.Remove(encodedAttachmentName.Length - encodingtoken.Length, encodingtoken.Length);

        return encodedAttachmentName;
    }
}

Answer 1

事实证明有一个错误报告 - https://connect.microsoft.com/VisualStudio/feedback/details/696372/filename-encoding-error-when-encoding-utf-8-and-encoded-name-exceeds-the-length-of-a-single-mime-header-line#details

和一篇kb文章来修复带有特殊字符的长名称的初始问题。 http://support.microsoft.com/kb/2402064

安装kb后，

我改变了

mm.Attachments.Add（CreateAttachment（attachment，attachment.Name））; mm.Attachments.Add（CreateAttachment（attachment2，attachment2.Name））;

回到应该是什么 mm.Attachments.Add（附着）; mm.Attachments.Add（attachment2）;

一切正常..

通过电子邮件发送带有长名称和重音符号的附件

1 个答案: