SmtpClient无法发送电子邮件

Question

我尝试了两个应用程序，一个在java中，一个在C＃中。 Java应用程序可以成功发送电子邮件，但C＃不能。下面是两个应用： 1.Java

final String username = "myaccount@mydomain"; 
final String password = "mypassword"; 
String smtpHost = "smtp.mydomain"; 

Properties props = new Properties(); 
props.put("mail.smtp.auth", "true"); 
props.put("mail.smtp.host", smtpHost); 
props.put("mail.smtp.port", "465"); 
props.put("mail.smtp.socketFactory.port", "465"); 
props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory"); 

Session session = Session.getDefaultInstance(props, new javax.mail.Authenticator() { 
    @Override 
    protected PasswordAuthentication getPasswordAuthentication() { 
     return new PasswordAuthentication(username, password); 
    } 
}); 

Message message = new MimeMessage(session); 
message.setFrom(new InternetAddress(username)); 
message.setRecipients(Message.RecipientType.TO, InternetAddress.parse(username)); 
message.setSubject("Test send email"); 
message.setText("Hi you!"); 
Transport.send(message); 

2.C＃

string username = "myaccount@mydomain"; 
string password = "mypassword"; 
string smtpHost = "smtp.mydomain"; 

SmtpClient mailClient = new SmtpClient(smtpHost, 465); 
mailClient.Host = smtpHost; 
mailClient.Credentials = new NetworkCredential(username, password); 
mailClient.EnableSsl = true; 
MailMessage message = new MailMessage(username, username, "test send email", "hi u"); 

mailClient.Send(message); 

那么，什么是我在C＃应用程序发出的错误呢？为什么它不能发送电子邮件？

编辑： 我已阅读这个问题How can I send emails through SSL SMTP with the .NET Framework?它的工作原理。不推荐使用System.Web.Mail.SmtpMail，但System.Net.Mail.SmtpClient不适用。为什么？

3，本C＃代码做工精细：

System.Web.Mail.MailMessage myMail = new System.Web.Mail.MailMessage(); 
myMail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpserver","smtp.mydomain"); 
myMail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpserverport","465"); 
myMail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendusing","2"); 
myMail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate", "1"); 
myMail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendusername", "myaccount@mydomain"); 
myMail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendpassword", "mypassword"); 
myMail.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpusessl", "true"); 
myMail.From = "myaccount@mydomain"; 
myMail.To = "myaccount@mydomain"; 
myMail.Subject = "new code"; 
myMail.BodyFormat = System.Web.Mail.MailFormat.Html; 
myMail.Body = "new body"; 
System.Web.Mail.SmtpMail.SmtpServer = "smtp.mydomain:465"; 
System.Web.Mail.SmtpMail.Send(myMail); 

Answer 1

你可以试试这个代码。还在单独的线程中发送电子邮件。

using System.Net.Mail; 

public static void Email(string Content, string To, string Subject, List<string> Attach = null, string User = "sender@sender.com", string Password = "MyPassword", string Host = "mail.sender.com", ushort Port = 587, bool SSL = false) 
{ 
    var Task = new System.Threading.Tasks.Task(() => 
    { 
     try 
     { 
      MailMessage Mail = new MailMessage(); 

      Mail.From = new MailAddress(User); 
      Mail.To.Add(To); 
      Mail.Subject = Subject; 
      Mail.Body = Content; 

      if (null != Attach) Attach.ForEach(x => Mail.Attachments.Add(new System.Net.Mail.Attachment(x))); 

      SmtpClient Server = new SmtpClient(Host); 

      Server.Port = Port; 
      Server.Credentials = new System.Net.NetworkCredential(User, Password); 
      Server.EnableSsl = SSL; 
      Server.Send(Mail); 
     } 
     catch (Exception e) 
     { 
      MessageBox.Show("Email send failed."); 
     } 
    }); 

    Task.Start(); 
} 

Answer 2

.NET System.Net.Mail.SmtpClient类无法处理隐式SSL连接。隐式SSL连接通过端口465发送，因为在您的示例中配置了客户端。

您可以使用像AIM（Aegis Implicit Mail）这样的第三方库来发送隐式SSL消息。