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Attachment Class

Represents an attachment to an e-mail.

Namespace:  System.Net.Mail
Assembly:  System (in System.dll)
public class Attachment : AttachmentBase

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.

The following code example demonstrates attaching a file to an e-mail message.

		public static void CreateMessageWithAttachment(string server)
		{
			// Specify the file to be attached and sent.
			// This example assumes that a file named Data.xls exists in the
			// current working directory.
			string file = "data.xls";
			// Create a message and set up the recipients.
			MailMessage message = new MailMessage(
			   "jane@contoso.com",
			   "ben@contoso.com",
			   "Quarterly data report.",
			   "See the attached spreadsheet.");

			// Create  the file attachment for this e-mail message.
			Attachment data = new Attachment(file, MediaTypeNames.Application.Octet);
			// Add time stamp information for the file.
			ContentDisposition disposition = data.ContentDisposition;
			disposition.CreationDate = System.IO.File.GetCreationTime(file);
			disposition.ModificationDate = System.IO.File.GetLastWriteTime(file);
			disposition.ReadDate = System.IO.File.GetLastAccessTime(file);
			// Add the file attachment to this e-mail message.
			message.Attachments.Add(data);

			//Send the message.
			SmtpClient client = new SmtpClient(server);
			// Add credentials if the SMTP server requires them.
			client.Credentials = CredentialCache.DefaultNetworkCredentials;

      try {
			  client.Send(message);
			}
			catch (Exception ex) {
			  Console.WriteLine("Exception caught in CreateMessageWithAttachment(): {0}", 
                    ex.ToString() );			  
			}
			// Display the values in the ContentDisposition for the attachment.
			ContentDisposition cd = data.ContentDisposition;
			Console.WriteLine("Content disposition");
			Console.WriteLine(cd.ToString());
			Console.WriteLine("File {0}", cd.FileName);
			Console.WriteLine("Size {0}", cd.Size);
			Console.WriteLine("Creation {0}", cd.CreationDate);
			Console.WriteLine("Modification {0}", cd.ModificationDate);
			Console.WriteLine("Read {0}", cd.ReadDate);
			Console.WriteLine("Inline {0}", cd.Inline);
			Console.WriteLine("Parameters: {0}", cd.Parameters.Count);
			foreach (DictionaryEntry d in cd.Parameters)
			{
				Console.WriteLine("{0} = {1}", d.Key, d.Value);
			}
			data.Dispose();
		}


public:
    static void CreateMessageWithAttachment(String* server)
    {
        // Specify the file to be attached and sent.
        // This example assumes that a file named Data.xls exists in the
        // current working directory.
        String* file = S"data.xls";
         // Create a message and set up the recipients.
         MailMessage* message = new MailMessage(
            S"jane@contoso.com", 
            S"ben@contoso.com",
            S"Quarterly data report.", 
            S"See the attached spreadsheet.");

        // Create  the file attachment for this e-mail message.
        Attachment* data = new Attachment();
        data->SetContentFromFile(file, 0, MediaTypeNames::Application::Octet);
        // Add time stamp information for the file.
        ContentDisposition* disposition = data->ContentDisposition;
        disposition->CreationDate = System::IO::File::GetCreationTime(file);
        disposition->ModificationDate = System::IO::File::GetLastWriteTime(file);
        disposition->ReadDate = System::IO::File::GetLastAccessTime(file);
        // Add the file attachment to this e-mail message.
        message->Attachments->Add(data);
        //Send the message.
        SmtpClient* client = new SmtpClient(server);
        // Add credentials if the SMTP server requires them.
        client->Credentials = CredentialCache::DefaultNetworkCredentials;
        client->Send(message);
        // Display the values in the ContentDisposition for the attachment.
        ContentDisposition* cd = data->ContentDisposition;
        Console::WriteLine(S"Content disposition");
        Console::WriteLine(cd);
        Console::WriteLine(S"File {0}",cd->FileName);
        Console::WriteLine(S"Size {0}", __box(cd->Size));
        Console::WriteLine(S"Creation {0}", __box(cd->CreationDate));
        Console::WriteLine(S"Modification {0}", __box(cd->ModificationDate));
        Console::WriteLine(S"Read {0}", __box(cd->ReadDate));
        Console::WriteLine(S"Inline {0}", __box(cd->Inline));
        Console::WriteLine(S"Parameters: {0}", __box(cd->Parameters->Count));
        IEnumerator* myEnum1 = cd->Parameters->GetEnumerator();
        while (myEnum1->MoveNext())
        {
            DictionaryEntry* d = __try_cast<DictionaryEntry*>(myEnum1->Current);
            Console::WriteLine(S"{0} = {1}", d->Key, d->Value);
        }
        data->Dispose();
        client->Dispose();
    }


Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0
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