SendMail SendAsync

Question

C#和sendmail异步有一个奇怪的问题。当我使用普通发送方法时，一切正常，我的电子邮件将发送到正确的SMTP-Server。但是当我使用SendAsync-方法时，它不起作用。

mailClient.SendCompleted += SendCompleted;

private static void SendCompleted (object sender, AsyncCompletedEventArgs e)
{
  string token = (string) e.UserState;

  if (e.Cancelled)
  {
    MessageBox.Show (string.Format ("{0}\n\"{1}\"", Application.Current.FindResource ("MailCannotSend"), token), LogFile.MSGBOX_ERROR, MessageBoxButton.OK, MessageBoxImage.Error);
    return;
  }

  MessageBox.Show (e.Error != null ? string.Format ("{0}\n\"{1}\"", e.Error, token) : "Complete!", LogFile.MSGBOX_ERROR, MessageBoxButton.OK, MessageBoxImage.Error);
}

SendAsync-方法总是在e.Cancelled中运行，没有任何异常或错误。我真的不知道为什么。

有什么线索吗线索？谢谢!

更新

以下是完整的代码：

public void InitClient ()
{
  try
  {
    mailClient = new SmtpClient (SettingsHelper.TailSettings.AlertSettings.SmtpSettings.SmtpServerName, SettingsHelper.TailSettings.AlertSettings.SmtpSettings.SmtpPort)
    {
      UseDefaultCredentials = false,
      Timeout = 30000,
      DeliveryMethod = SmtpDeliveryMethod.Network
    };
    string decryptPassword = StringEncryption.Decrypt (SettingsHelper.TailSettings.AlertSettings.SmtpSettings.Password, LogFile.ENCRYPT_PASSPHRASE);
    NetworkCredential authInfo = new NetworkCredential (SettingsHelper.TailSettings.AlertSettings.SmtpSettings.LoginName, decryptPassword);
    mailClient.Credentials = authInfo;
    mailClient.SendCompleted += SendCompleted;

    if (SettingsHelper.TailSettings.AlertSettings.SmtpSettings.SSL)
      mailClient.EnableSsl = true;
    if (SettingsHelper.TailSettings.AlertSettings.SmtpSettings.TLS)
      ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls;

    MailAddress from = new MailAddress (SettingsHelper.TailSettings.AlertSettings.SmtpSettings.FromAddress);
    MailAddress to = new MailAddress (SettingsHelper.TailSettings.AlertSettings.EMailAddress);

    mailMessage = new MailMessage (from, to)
    {
      Subject = SettingsHelper.TailSettings.AlertSettings.SmtpSettings.Subject,
      SubjectEncoding = System.Text.Encoding.UTF8,
      BodyEncoding = System.Text.Encoding.UTF8,
      IsBodyHtml = false
    };
}
  catch (Exception ex)
  {
    ErrorLog.WriteLog (ErrorFlags.Error, GetType ( ).Name, string.Format ("{1}, exception: {0}", ex, System.Reflection.MethodBase.GetCurrentMethod ( ).Name));
  }
}

/// <summary>
/// Send E-Mail
/// </summary>
/// <param name="userToken">User token</param>
/// <param name="bodyMessage">Message to be send</param>
public void SendMail (string userToken, string bodyMessage = null)
{
  try
  {
    string userState = userToken;

    if (bodyMessage != null)
      mailMessage.Body = bodyMessage;

    if (String.Compare (userState, "testMessage", StringComparison.Ordinal) == 0)
      mailMessage.Body = string.Format ("Testmail from {0}", LogFile.APPLICATION_CAPTION);

    mailClient.SendAsync (mailMessage, userToken);

    if (String.Compare (userState, "testMessage", StringComparison.Ordinal) == 0)
      return;
}
  catch (Exception ex)
  {
    ErrorLog.WriteLog (ErrorFlags.Error, GetType ( ).Name, string.Format ("{1}, exception: {0}", ex, System.Reflection.MethodBase.GetCurrentMethod ( ).Name));
  }
}

Answer 1

SendAsync是异步的，它将在将来完成。显然，在触发SendMail之前，调用SendCompleted结束的方法的范围。例如，控制台应用程序可能在您有机会处理此事件并处理异步操作完成之前就结束了。

任何进一步的建议都将取决于应用程序的执行环境是什么: ASP.NET、WCF、Console、WinForms、WPF等等。