通過GMail和.NET 4發送電子郵件

Question

.NET 4在發送電子郵件時是否有任何問題？ 我有一個.NET 3.5解決方案，它可以正常工作，然后將該解決方案遷移到.NET 4，但它不起作用。 沒有改變！

注意：我得到此異常：

System.Net.Mail.SmtpException：SMTP服務器需要安全連接，或者客戶端未通過身份驗證。 服務器響應為：5.5.1需要身份驗證。 在System.Net.Mail.MailCommand.CheckResponse（SmtpStatusCode statusCode，字符串響應）中了解更多信息。
在System.Net.Mail.MailCommand.Send（SmtpConnection conn，Byte []命令，字符串從）
在System.Net.Mail.SmtpTransport.SendMail（MailAddress發件人，MailAddressCollection收件人，字符串deliveryNotify，SmtpFailedRecipientException＆異常）
在System.Net.Mail.SmtpClient.Send（MailMessage消息）
在 ...

這是我的代碼：

public static void SendEmail(
    this Email email)
{
    if (email.MailingSettings == null) throw new ArgumentNullException("email.MailingSettings", "specify email.MailingSettings");

    var settings = email.MailingSettings;

    if (string.IsNullOrEmpty(email.Sender)) throw new ArgumentException("email.Sender", "specify a sender");
    if (email.Recipients == null) throw new ArgumentNullException("email.Recipients", "specify at least a recipient");
    if (email.Recipients.Length == 0) throw new ArgumentNullException("email.Recipients", "specify at least a recipient");
    if (string.IsNullOrEmpty(settings.SMTPHost)) throw new ArgumentException("email.SMTPHost", "specify email.SMTPHost");

    var mail = new MailMessage();

    if (string.IsNullOrEmpty(email.SenderDisplayName))
        mail.From = new MailAddress(email.Sender);
    else
        mail.From = new MailAddress(email.Sender, email.SenderDisplayName);

    if (!string.IsNullOrEmpty(email.ReplyTo))
    {
        if (string.IsNullOrEmpty(email.ReplyToDisplayName))
        {
            mail.ReplyToList.Add(new MailAddress(email.ReplyTo));
        }
        else
        {
            mail.ReplyToList.Add(new MailAddress(email.ReplyTo, email.ReplyToDisplayName));
        }
    }

    foreach (string recipient in email.Recipients)
        mail.To.Add(new MailAddress(recipient));

    mail.Subject = email.Subject;
    mail.Body = email.Body;
    mail.IsBodyHtml = settings.IsBodyHtml;

    if (email.CC != null && email.CC.Length > 0)
        foreach (string cci in email.CC)
            mail.CC.Add(cci);

    if (email.BCC != null && email.BCC.Length > 0)
        foreach (string bcci in email.BCC)
            mail.Bcc.Add(bcci);

    if (email.Attachments != null)
        foreach (var ifn in email.Attachments)
            mail.Attachments.Add(
                new Attachment(
                    new MemoryStream(
                        ifn.Content),
                    ifn.FileName));

    var smtpPort = settings.SMTPPort > 0 ? settings.SMTPPort : 25;

    var smtpClient = new SmtpClient(settings.SMTPHost, smtpPort);
    smtpClient.EnableSsl = settings.EnableSsl;

    if (!string.IsNullOrEmpty(settings.SMTPUser))
    {
        smtpClient.UseDefaultCredentials = false;

        var smtpPassword = settings.SMTPPassword == null ? string.Empty : settings.SMTPPassword;

        NetworkCredential netCred;
        if (string.IsNullOrEmpty(settings.SMTPDomain))
            netCred = new NetworkCredential(settings.SMTPUser, smtpPassword);
        else
            netCred = new NetworkCredential(settings.SMTPUser, smtpPassword, settings.SMTPDomain);

        smtpClient.Credentials = netCred;
    }
    else
        smtpClient.Credentials = CredentialCache.DefaultNetworkCredentials;

    smtpClient.Timeout = 180 * 1000;
    smtpClient.DeliveryMethod = SmtpDeliveryMethod.Network;

    ServicePointManager.ServerCertificateValidationCallback =
        delegate(object s, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
        { return true; };

    smtpClient.Send(mail);
}

Answer 1

如果所有內容均符合所發布的代碼和評論，那么我可以說您已對Google帳戶啟用了兩步驗證 ，在這種情況下，您需要生成“ 專用密碼”。

Answer 2

該代碼正確無誤。 問題是在GMail方面解決的（未檢測到原因和方式）。

Answer 3

嘗試使用這個：

try
{
    string smtpAddress = "smtp.gmail.com";
    int portNumber = 587;
    bool enableSSL = true;
    string emailFrom = "senderemail@gmail.com";
    string password = "password";
    string emailTo = "receiver@gmail.com";
    string subject = "Halo!";
    string body = "Halo, Mr. SMTP";
    MailMessage mail = new MailMessage();
    mail.From = new MailAddress(emailFrom);
    mail.To.Add(emailTo);
    mail.Subject = subject;
    mail.Body = body;
    mail.IsBodyHtml = true;

    using (SmtpClient smtp = new SmtpClient(smtpAddress, portNumber))
    {
        smtp.Credentials = new NetworkCredential(emailFrom, password);
        smtp.EnableSsl = enableSSL;
        smtp.Send(mail);
    }
}
catch (Exception ex)
{
    MessageBox.Show(ex.ToString());
}

*請注意，在此之前，您需要激活以下命令： https : //myaccount.google.com/lesssecureapps

然后構建並運行代碼..太神奇了.. :)