POP3协议的问题，快来看看

Question

为何用户名和密码都通过，到状态就出错了呢？代码是差不多的啊！            string userName = "xxx";
            string password = "xxx";
            string CRLF = "\r\n";
       
            TcpClient client = new TcpClient("pop.163.com", 110);
            NetworkStream netStream = client.GetStream();
            StreamReader rdStream = new StreamReader(client.GetStream());
            string data;
            byte[] szData;            data = "USER" + userName + CRLF;
            szData = System.Text.Encoding.ASCII.GetBytes(data.ToCharArray());
            netStream.Write(szData, 0, szData.Length);
            Console.WriteLine(rdStream.ReadLine());            data = "PASS" + password + CRLF;
            szData = System.Text.Encoding.ASCII.GetBytes(data.ToCharArray());
            netStream.Write(szData, 0, szData.Length);
            Console.WriteLine(rdStream.ReadLine());            //下面的就出问题了
            data = "STAT" + CRLF;
            szData = System.Text.Encoding.ASCII.GetBytes(data.ToCharArray());
            netStream.Write(szData, 0, szData.Length);
            Console.WriteLine(rdStream.ReadLine());

Answer 1

USER空格用户名
PASS空格口令

Answer 2

多谢！不过想再问一句：
NetworkStream netStream = client.GetStream();
这句代码得到的是一个引用吧？这样好吗？应该怎样写？

Answer 3

可以这样，不过个人认为最好加上
try{
   stream = client.GetStream();
   ...
}
catch