c# – 具有重音的MailMessage附件文件名

我正在尝试发送带有附加Excel文件名的 HTML电子邮件.这一切都运行良好,直到我发送其附件名称包含重音字母的消息:-(我尝试过的每一种解决方法都失败了.

原始代码：

var attachment = new Attachment(
       new MemoryStream(excelFileContents),"simplefilename.xls");

这个工作正常.
但是,如果我用“échec.xls”替换“simplefilename.xls”,附件就会被填充(名称和内容).

我试过这些,但无济于事：

var attachment = new Attachment(
       new MemoryStream(excelFileContents),new System.Net.Mime.ContentType("application/vnd.ms-excel"));
  attachment.Name = "échec.xls";

最后一个更糟糕：SmtpClient.Send()抛出异常,抱怨文件名中的é：

var attachment = new Attachment(
       new MemoryStream(excelFileContents),new System.Net.Mime.ContentType("application/vnd.ms-excel"));
  attachment.Contentdisposition.FileName = "échec.xls";

我一直在敲打这个问题太久了.任何灯都热烈欢迎！

解决方法

我终于找到了一个有效的答案.

http://social.msdn.microsoft.com/Forums/en-US/dotnetframeworkde/thread/b6c764f7-4697-4394-b45f-128a24306d55

除了marcel Roma的帖子外,内容为德语.我将他的代码放入我的应用程序中.我能够发出带有重音的pdf,我们看到了附件而不是垃圾.

所以这里是：

public class AttachmentHelper
{
    public static System.Net.Mail.Attachment CreateAttachment(string attachmentFile,string displayName,TransferEncoding transferEncoding)
    {
        System.Net.Mail.Attachment attachment = new System.Net.Mail.Attachment(attachmentFile);
        attachment.TransferEncoding = transferEncoding;

        string tranferEncodingMarker = String.Empty;
        string encodingMarker = String.Empty;
        int maxChunkLength = 0;

        switch (transferEncoding)
        {
            case TransferEncoding.Base64:
                tranferEncodingMarker = "B";
                encodingMarker = "UTF-8";
                maxChunkLength = 30;
                break;
            case TransferEncoding.QuotedPrintable:
                tranferEncodingMarker = "Q";
                encodingMarker = "ISO-8859-1";
                maxChunkLength = 76;
                break;
            default:
                throw (new ArgumentException(String.Format("The specified TransferEncoding is not supported: {0}",transferEncoding,"transferEncoding")));
        }

        attachment.NameEncoding = Encoding.GetEncoding(encodingMarker);

        string encodingtoken = String.Format("=?{0}?{1}?",encodingMarker,tranferEncodingMarker);
        string softbreak = "?=";
        string encodedAttachmentName = encodingtoken;

        if (attachment.TransferEncoding == TransferEncoding.QuotedPrintable)
            encodedAttachmentName = HttpUtility.UrlEncode(displayName,Encoding.Default).Replace("+"," ").Replace("%","=");
        else
            encodedAttachmentName = System.Convert.ToBase64String(Encoding.UTF8.GetBytes(displayName));

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

        return attachment;
    }

    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;
    }

    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;
    }
}

以下列方式使用它：

static void Main(string[] args)
{
    string smtpServer = String.Empty;
    string userName = String.Empty;
    string password = String.Empty;
    string attachmentFilePath = String.Empty;
    string displayName = String.Empty;

    System.Net.Mail.SmtpClient client = new System.Net.Mail.SmtpClient(smtpServer);
    client.Credentials = new System.Net.NetworkCredential(userName,password);

    var msg = new System.Net.Mail.MailMessage(fromAddress,toAddress,"Subject","Body");
    System.Net.Mail.Attachment attachment =
         AttachmentHelper.CreateAttachment(attachmentFilePath,displayName,TransferEncoding.Base64);

    msg.Attachments.Add(attachment);
    client.Send(msg);
}