如何检查电子邮件状态是否已在c＃中删除

Question

Currently i am sending mail through SMTP Code is given below

SmtpClient client = new SmtpClient();
client.DeliveryMethod = SmtpDeliveryMethod.Network;
//client.EnableSsl = true;
client.Send(msg);

I have to check the delievery status that mail is delievered or not using smtp exception using code

Answer 1

While @Chase is technically correct, it's possible to get delivery status notifications if the SMTP servers along the route support this extension.

I'm not aware of a way to do this with System.Net.Mail, but with MailKit , you can actually request delivery status notifications for your recipients.

In MailKit, the first thing you'll need to do (until I figure out a nicer API for this) is to setup your own SmtpClient class like this:

class MySmtpClient : SmtpClient
{
    public MySmtpClient ()
    {
    }

    /// <summary>
    /// Get the envelope identifier to be used with delivery status notifications.
    /// </summary>
    /// <remarks>
    /// <para>The envelope identifier, if non-empty, is useful in determining which message
    /// a delivery status notification was issued for.</para>
    /// <para>The envelope identifier should be unique and may be up to 100 characters in
    /// length, but must consist only of printable ASCII characters and no white space.</para>
    /// <para>For more information, see rfc3461, section 4.4.</para>
    /// </remarks>
    /// <returns>The envelope identifier.</returns>
    /// <param name="message">The message.</param>
    protected override string GetEnvelopeId (MimeMessage message)
    {
        // The Message-Id header is probably the easiest way to go...
        return message.MessageId;
    }

    /// <summary>
    /// Get the types of delivery status notification desired for the specified recipient mailbox.
    /// </summary>
    /// <remarks>
    /// Gets the types of delivery status notification desired for the specified recipient mailbox.
    /// </remarks>
    /// <returns>The desired delivery status notification type.</returns>
    /// <param name="message">The message being sent.</param>
    /// <param name="mailbox">The mailbox.</param>
    protected override DeliveryStatusNotification? GetDeliveryStatusNotifications (MimeMessage message, MailboxAddress mailbox)
    {
        // Since you want to know whether the message got delivered or not,
        // you'll probably want to get notifications for Success and Failure.
        return DeliveryStatusNotification.Success | DeliveryStatusNotification.Failure;
    }
}

Then, once you have that, you'd use it like this:

using (var client = new MySmtpClient ()) {
    client.Connect ("smtp.gmail.com", 465, true);
    client.Authenticate ("username", "password");
    client.Send (message);
    client.Disconnect (true);
}

What will now happen is that whenever there is a success or failure notification, you'll get an email delivered to your account's Inbox (POP3 or IMAP depending on what you use) that will contain a multipart/report MIME part which will typically contain 3 other MIME parts: a human readable explanation, a message/delivery-status MIME part which will have a body that contains some key/value pairs and a third part which contains the original message (or sometimes just the headers).

Currently, MailKit does not have a special MIME class for dealing with message/delivery-status MIME parts, but you can work around this by parsing the content like this:

var mds = message.BodyParts.OfType<MimePart>.Where (x => x.ContentType.Matches ("message", "delivery-status")).FirstOrDefault ();
if (mds != null) {
    using (var memory = new MemoryStream ()) {
        mds.ContentObject.DecodeTo (memory);
        memory.Position = 0;

        // the content of a message/delivery-status MIME part is a
        // collection of header groups. The first group of headers
        // will contain the per-message status headers while each
        // group after that will contain status headers for a
        // particular recipient.
        var groups = new List<HeaderList> ();
        while (memory.Position < memory.Length)
            groups.Add (HeaderList.Load (memory));

        // TODO: take a look at the specific "headers" to get the info we 
        // care about. For more info on what these header field names and
        // values are, take a look at https://tools.ietf.org/html/rfc3464
    }
}

Update: I've added a MessageDeliveryStatus class to MimeKit that handles parsing the content of message/delivery-status MIME parts for you, but it may take up to 2 weeks before I make another release since I just made a release 2 days ago. Expect to find this new class in MimeKit 1.2.8 when I do release it.

Answer 2

You can't check it. Because you use SMTP , it's impossible to tell whether delivery succeeded or not. Mail is routed while being delivered. Some useful tricks are verify the email address is valid before you send it and set up a single no reply address as an actual inbox and then go into the email account using POP3 and look for bounce back messages. Details how SMTP works