Adding multiple attachments to e-mail from disc by iteration

Question

UPDATE I tested this with Excel documents instead of PDFs, and it worked. Why won't it work with PDFs??

I am trying to add X amount of attachments to an e-mail by iterating over a list of file path strings. Instead I get X attachments, but they're all copies of the same file. So the amount of attachments is correct, but their content is not.

This happens even though:

the PDF files are saved correctly on disk.
whilst debugging, the list of file paths is correct.
whilst debugging, file names and file paths are distinct.

I am using FluentEmail to send e-mails. Also, I am building upon the following example (see 'Multiple attachments' section).

I added Debug.WriteLine(path) just to check if I am able to correctly output the strings in the loop, which I were.

My method:

public async void SendInvoicesEmail() {

    try {

        using (SqlConnection con = new(ConnectionString.connectionString))
        using (SqlCommand cmd = new("query text", con)) {

            con.Open();

            SmtpSender sender = new SmtpSender(() => new SmtpClient(host: "smtp.office365.com") {

                EnableSsl = true,
                UseDefaultCredentials = false,
                DeliveryMethod = SmtpDeliveryMethod.Network,
                Credentials = new NetworkCredential("email", "password"),
                Port = 587
            });

            Email.DefaultSender = sender;
            IFluentEmail newEmail = Email
                .From("email")
                .To("email")
                .Subject("subject text")
                .Body("body text");

            var attachList = new List();

            // SourcePathList contains all the file paths I need to reference.
            foreach (string path in SourcePathList) {

                string fileName = Path.GetFileName(path);

                var attachment = new FluentEmail.Core.Models.Attachment {

                    Data = File.OpenRead(path),
                    ContentType = "application/pdf",
                    Filename = $"{fileName}"
                };

                attachList.Add(attachment);
                Debug.WriteLine(path);
            }

            newEmail.Attach(attachList);
            SourcePathList.Clear();
            FluentEmail.Core.Models.SendResponse result = await newEmail.SendAsync();

            if (result.Successful) {

                cmd.ExecuteNonQuery();
            }
        }

    } catch (Exception ex) {

        MessageBox.Show(ex.Message, "Message", MessageBoxButton.OK, MessageBoxImage.Information);
    }
}

I have tried:

Using newEmail.AttachFromFilename.
Using newEmail.Send instead of .SendAsync.
Iterating over array instead of list.
Changed my SMTP host.
Tried using ContentType for older PDFs (even though I have updated software): "application/x-pdf".

But none of the above made any difference.

The three items present are distinct, yet only the last item is added as file in the 3 attachments. Does ContentId matter?

user_7532693 · Answer

I think stream object is not getting refresh in loop and it is adding same file content for each attachment.
you should use your stream object in using statement as below

I am also using similar functionality on my web using System.Net.Mail

Earlier I have suggested an untested code, which had a bug. Now I have tested your code again and it's working as expected. here is complete method which I have run in a MVC controller.

public async void SendInvoicesEmail()
        {
            try
            {
                SmtpSender sender = new SmtpSender(() => new SmtpClient(host: "smtp.sendgrid.net")
                {

                    EnableSsl = true,
                    UseDefaultCredentials = false,
                    DeliveryMethod = SmtpDeliveryMethod.Network,
                    Credentials = new NetworkCredential("user", "password"),
                    Port = 587
                });

                Email.DefaultSender = sender;
                IFluentEmail newEmail = Email
                    .From("Admin@admin.com")
                    .To("user@user.com")
                    .Subject("I am feeling lucky")
                    .Body("This email is for stack overflow problem solution.");

                var attachList = new List();
                // SourcePathList contains all the file path on my machine.
                var SourcePathList = new List
                {
                    "C:\Consolidate_09122021085902.xlsx",
                    "C:\PaySlip_15022022075604.xlsx",
                    "C:\RateCard_14022022104134.xlsx"
                };
                
                foreach (string path in SourcePathList)
                {

                    string fileName = Path.GetFileName(path);
                    var attachment = new FluentEmail.Core.Models.Attachment
                    {

                        Data = System.IO.File.OpenRead(path),
                        ContentType = "application/pdf",
                        Filename = $"{fileName}"
                    };

                    attachList.Add(attachment);
                    Debug.WriteLine(path);
                }

                newEmail.Attach(attachList);
                SourcePathList.Clear();
                FluentEmail.Core.Models.SendResponse result = await newEmail.SendAsync();

            }
            catch (Exception ex)
            {
                // write log file
            }
        }

Here is Email Output

Adding multiple attachments to e-mail from disc by iteration

1 Answers