C# （这个想法）

我的email类有两个属性，一个是Message（System.Net.Mail.MailMessage），另一个是Server（System.Net.Mail.SmtpClient），这就是本例中要处理的内容

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在我的服务中发送电子邮件的每一个实例都以这种方式实现后，我收到了数百封电子邮件，但我没有遇到任何问题。

我不打算为这封邮件提供答案，因为我对SMTP的了解不够，无法对此感到满意。但是，这听起来确实像是一个环境问题（可能在IIS设置中）。您是否使用1）“localhost”作为smtp.Host 2）smtp.Host的远程服务器和/或3）特定IP而不是主机名？我的邮件主机是按名称引用的。例如“交换”。我已经通过ping服务器测试了DNS。这是成功的。我还测试了通过telnet到端口25的端口访问。这也是成功的。我已经在另一台机器上测试了代码，并且能够发送消息。在我看来，我需要在机器上安装某种类型的SMTP服务/协议。代码失败的计算机是Windows Vista Business。测试在Windows Server 2008 Standard上成功。请参阅：我很难找到任何确认using语句在完成时发送QUIT的内容。简而言之，如何在不使用using语句的情况下优雅地关闭连接。如果查看SmtpClient.Dispose（）的文档，您将看到以下内容：“向SMTP服务器发送退出消息，优雅地结束TCP连接，并释放System.Net.Mail.SmtpClient类的当前实例使用的所有资源。”

namespace LabDemos
{
    class Program
    {
        static void Main(string[] args)
        {
            Mailer m = new Mailer();
            m.test();    
        }
    }
}

namespace LabDemos
{
    class MyMailer
    {    
        List<string> _to = new List<string>();
        List<string> _cc = new List<string>();
        List<string> _bcc = new List<string>();
        String _msgFrom = "";
        String _msgSubject = "";
        String _msgBody = "";            

        public void test(){
        //create the mail message
        MailMessage mail = new MailMessage();

        //set the addresses
        mail.From = new MailAddress("me@domain.com");            

        //set the content
        mail.Subject = "This is an email";
        mail.Body = "this is a sample body";
        mail.IsBodyHtml = false;    

        //send the message
        SmtpClient smtp = new SmtpClient();
        smtp.Host = "emailservername";
        smtp.Port = 25;
        smtp.UseDefaultCredentials = true;
        smtp.Send(mail);            
    }
}

Inner Exception
{"Unable to read data from the transport connection: net_io_connectionclosed."}

Stack Trace
"   at System.Net.Mail.SmtpReplyReaderFactory.ProcessRead(Byte[] buffer, Int32 offset, Int32 read, Boolean readLine)\r\n   at System.Net.Mail.SmtpReplyReaderFactory.ReadLines(SmtpReplyReader caller, Boolean oneLine)\r\n   at System.Net.Mail.SmtpReplyReaderFactory.ReadLine(SmtpReplyReader caller)\r\n   at System.Net.Mail.SmtpConnection.GetConnection(String host, Int32 port)\r\n   at System.Net.Mail.SmtpTransport.GetConnection(String host, Int32 port)\r\n   at System.Net.Mail.SmtpClient.GetConnection()\r\n   at System.Net.Mail.SmtpClient.Send(MailMessage message)"


Outer Exception
  System.Net.Mail.SmtpException was unhandled
  Message="Failure sending mail."
  Source="System"
  StackTrace:
       at System.Net.Mail.SmtpClient.Send(MailMessage message)
       at LabDemos.Mailer.test() in C:\Users\username\Documents\Visual Studio 2008\Projects\LabDemos\LabDemos\Mailer.cs:line 40
       at LabDemos.Program.Main(String[] args) in C:\Users\username\Documents\Visual Studio 2008\Projects\LabDemos\LabDemos\Program.cs:line 48
       at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
       at System.AppDomain.nExecuteAssembly(Assembly assembly, String[] args)
       at System.Runtime.Hosting.ManifestRunner.Run(Boolean checkAptModel)
       at System.Runtime.Hosting.ManifestRunner.ExecuteAsAssembly()
       at System.Runtime.Hosting.ApplicationActivator.CreateInstance(ActivationContext activationContext, String[] activationCustomData)
       at System.Runtime.Hosting.ApplicationActivator.CreateInstance(ActivationContext activationContext)
       at System.Activator.CreateInstance(ActivationContext activationContext)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssemblyDebugInZone()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException: System.IO.IOException
       Message="Unable to read data from the transport connection: net_io_connectionclosed."
       Source="System"
       StackTrace:
            at System.Net.Mail.SmtpReplyReaderFactory.ProcessRead(Byte[] buffer, Int32 offset, Int32 read, Boolean readLine)
            at System.Net.Mail.SmtpReplyReaderFactory.ReadLines(SmtpReplyReader caller, Boolean oneLine)
            at System.Net.Mail.SmtpReplyReaderFactory.ReadLine(SmtpReplyReader caller)
            at System.Net.Mail.SmtpConnection.GetConnection(String host, Int32 port)
            at System.Net.Mail.SmtpTransport.GetConnection(String host, Int32 port)
            at System.Net.Mail.SmtpClient.GetConnection()
            at System.Net.Mail.SmtpClient.Send(MailMessage message)
       InnerException: 

using(SmtpClient smtp = new SmtpClient())
{
    smtp.Host = "emailservername";
    smtp.Port = 25;
    smtp.UseDefaultCredentials = true;
    smtp.Send(mail)
}

 <smtp deliveryMethod="Network">
       <network host="localhost" port="25" defaultCredentials="false"/>
 </smtp>

With New clsEmail(True)
    With .Message
        .To.Add("user@domain.com")
        .Subject = msgSubject
        .Body = msgContents
    End With

    .Server.Send(.Message)
    .Server.Dispose()
    .Message.Dispose()
End With