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AttachmentBase Class

Namespace: System.Net.Mail

Assembly: System.Net.Mail.dll

Represents the base class for attachments that can be added to an e-mail message. This class is abstract and cannot be instantiated directly. Use specific classes like Attachment or LinkedResource.

Inheritance

System.Object
System.MarshalByRefObject
System.Net.Mail.AttachmentBase

Syntax

public abstract class AttachmentBase

Properties

The AttachmentBase class exposes the following properties:

ContentDisposition

System.Net.Mime.ContentDisposition

Gets the content disposition for the attachment.

ContentId

string

Gets or sets the content ID for the attachment. This is used for inline attachments (e.g., images in HTML content).

ContentType

System.Net.Mime.ContentType

Gets the content type of the attachment.

Name

string

Gets or sets the name of the attachment. This is the filename that will be displayed to the recipient.

TransferEncoding

System.Net.Mail.TransferEncoding

Gets or sets the transfer encoding for the attachment.

Methods

The AttachmentBase class does not define any public methods directly. Its derived classes may implement specific functionalities.

Remarks

The AttachmentBase class provides common functionality for attachments used in email messages. It defines properties for content disposition, content ID, content type, name, and transfer encoding. The actual attachment content is managed by derived classes such as Attachment (for files) and LinkedResource (for inline content like images within HTML).

When sending an email with attachments using SmtpClient, you add instances of derived classes to the AttachmentsCollection of a MailMessage object.

Example

The following example demonstrates how to create a MailMessage with a file attachment. Note that AttachmentBase is abstract, so we use the concrete Attachment class. 

using System.Net.Mail;

public class Mailer {
    public static void SendEmailWithAttachment() {
        // Create a new MailMessage object
        using (MailMessage message = new MailMessage()) {
            message.From = new MailAddress("sender@example.com");
            message.To.Add("recipient@example.com");
            message.Subject = "Email with Attachment";
            message.Body = "Please find the attached document.";

            // Create an Attachment object from a file
            string filePath = "path/to/your/document.pdf";
            Attachment attachment = new Attachment(filePath, System.Net.Mime.MediaTypeNames.Application.Pdf);

            // Add the attachment to the message
            message.Attachments.Add(attachment);

            // Configure the SmtpClient and send the email
            using (SmtpClient smtpClient = new SmtpClient("smtp.example.com")) {
                smtpClient.Credentials = new System.Net.NetworkCredential("sender@example.com", "your_password");
                smtpClient.Port = 587;
                smtpClient.EnableSsl = true;

                smtpClient.Send(message);
                Console.WriteLine("Email sent successfully with attachment!");
            }
        }
    }
}

See Also