I'm trying to send HTML e-mails with attached Excel filenames. It all worked well until I neded to send messages whose attachment name contains accented letters :-( Every workaround I've tried failed miserably.
Original code:
var attachment = new Attachment(
new MemoryStream(excelFileContents),
"simplefilename.xls");
This one works fine. However if I replace "simplefilename.xls" by "échec.xls", the attachment is garbaged (name and contents).
I tried these, to no avail:
var attachment = new Attachment(
new MemoryStream(excelFileContents),
new System.Net.Mime.ContentType("application/vnd.ms-excel"));
attachment.Name = "échec.xls";
The last one is even worse: SmtpClient.Send()
throws an exception, complaining about the é
in the filename:
var attachment = new Attachment(
new MemoryStream(excelFileContents),
new System.Net.Mime.ContentType("application/vnd.ms-excel"));
attachment.ContentDisposition.FileName = "échec.xls";
I've been banging my head on this one for way too long. Any lights warmly welcomed!
I finally came across an answer that worked.
The content is in German except for the post by Marcel Roma. I put in his code into my application. I was able to send out pdf with accents and we were to see the attachment instead of garbage.
So here it is:
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;
}
}
Use it in the following way:
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);
}