Send Uploaded File as attachment

Question

I am trying to get an uploaded file to be sent as an attachment in my ashx file. Here is the code I am using:

HttpPostedFile fileupload = context.Request.Files[0];

//filename w/o the path
string file = Path.GetFileName(fileupload.FileName);

MailMessage message = new MailMessage();

//*****useless stuff********
message.To.Add("[email protected]");
message.Subject = "test";
message.From = new MailAddress("[email protected]");
message.IsBodyHtml = true;
message.Body = "testing";
 //*****useless stuff********

//Fault line
message.Attachments.Add(new Attachment(file, MediaTypeNames.Application.Octet))

//Send mail 
SmtpClient smtp = new System.Net.Mail.SmtpClient("xxxx", 25);
smtp.UseDefaultCredentials = false;
smtp.Credentials = new NetworkCredential("xxx", "xxxx");
smtp.Send(message);

I am able to send the email without the attachment. Do I need to save the file first and then add to attachment?

Answer 1

You do NOT need to, nor should you, save attachments to the server unnecessarily. ASP Snippets has an article on how to do it in ASP.NET WebForms.

Doing it in C# MVC is even nicer:

public IEnumerable<HttpPostedFileBase> UploadedFiles { get; set; }

var mailMessage = new MailMessage();
// ... To, Subject, Body, etc

foreach (var file in UploadedFiles)
{
    if (file != null && file.ContentLength > 0)
    {
        try
        {
            string fileName = Path.GetFileName(file.FileName);
            var attachment = new Attachment(file.InputStream, fileName);
            mailMessage.Attachments.Add(attachment);
        }
        catch(Exception) { }
    }
}

Answer 2

Following in the footsteps of Serj Sagan, here's a handler using webforms, but with <input type="file" name="upload_your_file" /> instead of the <asp:FileUpload> control:

HttpPostedFile file = Request.Files["upload_your_file"];
if (file != null && file.ContentLength > 0)
{
    string fileName = Path.GetFileName(file.FileName);
    var attachment = new Attachment(file.InputStream, fileName);
    mailMessage.Attachments.Add(attachment);
}

This is useful if you don't need (or can't add) a runat="server" on your form tag.