Add mail attachment from filestream

To add a mail attachment from a file stream in C#, you can use the System.Net.Mail.Attachment class and pass the file stream to the Attachment constructor. Here's an example:

using System.IO;
using System.Net.Mail;

// assume you have a file stream object called "fileStream"
using (var attachment = new Attachment(fileStream, "attachmentName", "text/plain"))
{
    // add the attachment to the mail message
    mailMessage.Attachments.Add(attachment);
}

In this example, fileStream is the file stream object that contains the file you want to attach, attachmentName is the name of the attachment, and "text/plain" is the MIME type of the attachment.

You can also specify additional properties, such as the content disposition and the file name, using the Attachment constructor:

using (var attachment = new Attachment(fileStream, "attachmentName", "text/plain", "inline", "attachment.txt"))
{
    // add the attachment to the mail message
    mailMessage.Attachments.Add(attachment);
}

In this example, "inline" specifies the content disposition of the attachment, and "attachment.txt" is the file name of the attachment.

Make sure to dispose of the file stream object when you're done with it, either by using a using statement or by calling the Dispose method explicitly.

Here's a complete example:

using System.IO;
using System.Net.Mail;

// assume you have a file stream object called "fileStream"
using (var attachment = new Attachment(fileStream, "attachmentName", "text/plain"))
{
    // create a new mail message
    var mailMessage = new MailMessage();

    // add the attachment to the mail message
    mailMessage.Attachments.Add(attachment);

    // set the mail message properties
    mailMessage.From = new MailAddress("[email protected]");
    mailMessage.To.Add("[email protected]");
    mailMessage.Subject = "Test email with attachment";
    mailMessage.Body = "This is a test email with an attachment.";

    // send the mail message
    using (var smtpClient = new SmtpClient())
    {
        smtpClient.Send(mailMessage);
    }
}

This example creates a new mail message, adds the attachment to the message, sets the mail message properties, and sends the message using an SmtpClient object.

Mail Knowledge

Add mail attachment from filestream