Question

I have to mail several files to an e-mail address. The files needs to have .tcx file extension. These are in fact xml files (Garmin bicycle logs).

Apparently when the receiver gets the email, the attachement is named xxxxx.tcx.xml. How can I force the mailer not to change the attachment file name?

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Net.Mail;
using System.IO;

namespace stravamailer
{
    public partial class _Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            var files = Directory.GetFiles("E:\\JurgenS\\Downloads\\allrides");

            for (int i = 0; i < files.Length; i++)
            {
                MailMessage oMail = new MailMessage();
                oMail.Body = "";
                oMail.From = new MailAddress("[e-mail]","Jurgen Stillaert");
                oMail.Subject = "";
                oMail.To.Add(new MailAddress("[e-mail]"));
                Attachment att = new Attachment(files[i]);
                att.Name = Path.GetFileName(files[i]);
                oMail.Attachments.Add(att);

                SmtpClient oSmtp = new SmtpClient("uit.telenet.be");
                oSmtp.Send(oMail);
            }
        }
    }
}

Answer 1

The Attachment class is used with the MailMessage class. All messages
include a Body, which contains the content of the message. In addition
to the body, you might want to send additional files. These are sent
as attachments and are represented as Attachment instances. To add an
attachment to a mail message, add it to the MailMessage.Attachments
collection.

Attachment content can be a String, Stream, or file name. You can
specify the content in an attachment by using any of the Attachment
constructors.

The MIME Content-Type header information for the attachment is
represented by the ContentType property. The Content-Type header
specifies the media type and subtype and any associated parameters.
Use ContentType to get the instance associated with an attachment.

The MIME Content-Disposition header is represented by the
ContentDisposition property. The Content-Disposition header specifies
the presentation and file time stamps for an attachment. A
Content-Disposition header is sent only if the attachment is a file.
Use the ContentDisposition property to get the instance associated
with an attachment.

The MIME Content-Transfer-Encoding header is represented by the
TransferEncoding property.

Here is the source

Your solution is in this MSDN link. you should try MIME Content-Type.