Asp.Net Identity 2.0 - 如何使用SmtpClient实现IIdentityMessageService来执行异步SMTP？

Question

我已经为Asp.Net Identity 2.0实现了一个简单的EmailService(通过IIdentityMessageService界面.

    public class EmailService : IIdentityMessageService
{
    public Task SendAsync(IdentityMessage message)
    {
        // convert IdentityMessage to a MailMessage
        var email = 
           new MailMessage(new MailAddress("noreply@mydomain.com", "(do not reply)"), 
           new MailAddress(message.Destination))
        {
            Subject = message.Subject,
            Body = message.Body,
            IsBodyHtml = true
        };

        using (var client = new SmtpClient()) // SmtpClient configuration comes from config file
        {
            return client.SendMailAsync(email);
        }
    }
}

要发送电子邮件,我将通过UserManager:

await _userManager.SendEmailAsync(user.Id, "Confirm your account","Please confirm your account by clicking this link: <a href=\"" + callbackUrl + "\">link</a>");

问题是,System.Threading.Tasks.TaskCanceledException当我打电话时,我得到一个SendEmailAsync(),但不清楚为什么.

如果我同步发送电子邮件(client.Send(email)),一切正常.

所以我的问题是:

• 如何防止TaskCanceledException被抛出？(假设我能克服这个错误),

• 我应该如何在电子邮件发送回客户端时传达错误(即"此处没有此类用户"类型的响应来自SmtpClient？

Answer 1

您的问题是SmtpClient在发送电子邮件之前处理的问题.

两种方式:

• 等待SendMailAsync结果

  using (var client = new SmtpClient())
  {
      await client.SendMailAsync(email);
  }
  

• 注册SendCompleted事件并SmtpClient在发送消息后进行处理

  var client = new SmtpClient();
  client.SendCompleted += (s, e) => {
      client.Dispose();
  };
  return client.SendMailAsync(message);
  

Answer 2

您必须在方法上放置异步.

    public async Task SendAsync(IdentityMessage message)
    {
        using (SmtpClient client = new SmtpClient())
        {
                using (var mailMessage = new MailMessage("your@email.com", message.Destination, message.Subject, message.Body))
                {
                    await client.SendMailAsync(mailMessage);
                }
            }
        }
    }