C＃获取SMTP-服务器的SSL证书有效期从ServerCertificateValidationCallback

Question

返回值此刻我有了这个代码，以获得SMTP-服务器的有效期限：

namespace SMTPCert 
{ 
    public class SMTPCert 
    { 
     public static void GetSMTPCert(string ServerName) 
     { 
      ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(RemoteServerCertificateValidationCallback); 
      using (System.Net.Mail.SmtpClient S = new System.Net.Mail.SmtpClient(ServerName)) 
      { 
       S.EnableSsl = true; 
       using (System.Net.Mail.MailMessage M = new System.Net.Mail.MailMessage("test@example.com", "test@example.com", "Test", "Test")) 
       { 
        try 
        { 
         S.Send(M); 
        } 
        catch (Exception) 
        { 
         return; 
        } 
       } 
      } 
     }
 

private static bool RemoteServerCertificateValidationCallback(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors) 
    { 
     Console.WriteLine(certificate); 
     return true; 
    } 
} 

}

我的问题是，我想将GetSMTPCert方法从void更改为字符串，以便将证书到期日期返回给我的主方法。 但目前我只能在RemoteServerCertificateValidationCallback方法中获得到期日期，并且无法从那里返回。是否有任何可能的方法获取证书到期日期到我的GetSMTPCert方法，然后将其返回到我的主要方法？

有关其他方式获取SMTP服务器的SSL证书过期日期的建议也是受欢迎的。

Answer 1

好吧我解决了这个问题，通过将类型字符串“CertificateDaysLeft”的公共静态字段添加到我的SMTPCert类。

namespace SMTPCert 
{ 
    public static string CertificateDaysLeft; 

    public static string GetSMTPCert(string ServerName) 
    { 
     ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(RemoteServerCertificateValidationCallback); 
     using (System.Net.Mail.SmtpClient S = new System.Net.Mail.SmtpClient(ServerName)) 
     { 
      S.EnableSsl = true; 
      using (System.Net.Mail.MailMessage M = new System.Net.Mail.MailMessage("test@example.com", "test@example.com", "Test", "Test")) 
      { 
       try 
       { 
        S.Send(M); 
        string daysLeft = CertificateDaysLeft; 
        return daysLeft; 
       } 
       catch (Exception) 
       { 
        string daysLeft = CertificateDaysLeft; 
        return daysLeft; 
       } 
      } 
     } 
    } 

    private static bool RemoteServerCertificateValidationCallback(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors) 
    { 
     DateTime ExpirDate = Convert.ToDateTime(certificate.GetExpirationDateString()); 
     string DaysLeft = Convert.ToString((ExpirDate - DateTime.Today).Days); 
     CertificateDaysLeft = DaysLeft; 
     Console.WriteLine(certificate); 
     return true; 
    } 
} 

}

我猜我想有点太复杂了。