SmtpClient.SendAsync（）不再起作用

Question

I have recently purchased a new computer, and now my e-mails never get sent, and there are NEVER any exceptions thrown or anything.

Can somebody please provide some samples that work using the SmtpClient class? Any help at all will be greatly appreciated.

Thank you

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Ok - I have added credentials now. And can SUCCESSFULLY SEND e-mail synchronously. But I can still not send them asynchronously.

Old: After trying to send e-mail synchronously, I receive the following exception:

Transaction failed. The server response was:

5.7.1 <myfriend@hotmails.com> : Relay access denied.

Answer 1

You can send mail through Async(). How means you should follow the below code,

smtpClient.SendCompleted += new SendCompletedEventHandler(smtpClient_SendCompleted);
smtpClient.SendAsync(mailMessage, mailMessage);

and, if you are using async, you need to also have the event handler like,

static void smtpClient_SendCompleted(object sender, System.ComponentModel.AsyncCompletedEventArgs e)
    {
        //to be implemented        
    }

By using this, you can send Mail.

Answer 2

You could first try the synchronous Send method to verify that everything is setup correctly with the SMTP server and that you don't get any exceptions:

var client = new SmtpClient("smtp.somehost.com");
var message = new MailMessage();
message.From = new MailAddress("from@somehost.com");
message.To.Add(new MailAddress("to@somehost.com"));
message.Subject = "test";
message.Body = "test body";
client.Send(message);

Remark: In .NET 4 SmtpClient implements IDisposable so make sure you wrap it in a using statement.