Using-statement with async call | Cancel operation?

Question

I'm facing a general question where I can't find a good example to try-it-for-myself. Google isn't a help neither.

Imagine a structure like this:

MailMessage mail = new MailMessage(sender, receiver);
using(SmtpClient client = new SmtpClient())
{
    client.Host ...
    client.Port ...

    mail.subject ...
    mail.body ...

    client.SendAsync(mail);
}

What if the server is slow and takes a while to accept the mail. Is it possible that the SmtpClient is disposed before the operation is done? Will it be canceled or broken in any way?

Is there a general answer for this? The servers in here are too fast, don't know how to do a try-out.

---

If thinking about canceling a BackgroundWorker it's always finishing the current operation. Could be the same here, or maybe not...

Answer 1

You can use the newer SendMailAsync method that returns a Task, and await that task:

MailMessage mail = new MailMessage(sender, receiver);
using(SmtpClient client = new SmtpClient())
{
    client.Host ...
    client.Port ...

    mail.subject ...
    mail.body ...

    await client.SendMailAsync(mail);
}

This will ensure that the client isn't disposed before SendMailAsync completes.

(of course, this means your method now has to be async as well)