邮箱登陆程序处的问题

Question

我用vc#做的一个简单的邮箱登陆的程序，邮箱地址 用户名和密码都没有错  邮箱是pop3.163.com（pop.163.com） 点连接后只提示用户名正确 密码却错误（可以肯定密码没有错），哪个高手给指点一下 问题处在什么地方了 ？？
运行结果是：
+ok welcome to core mail...........
+ok  core mail......
-err unable to log on
-err command not valid in this state
源代码如下：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Net;
using System.Net.Sockets;
using System.IO;namespace pop3server
{
    public partial class Form1 : Form
    {
        public TcpClient server;
        public NetworkStream netstrm;
        public StreamReader rdstrm;
        public string Data;
        public byte[] szData;
        public string CRLF = "\r\n";
        public Form1()
        {
            InitializeComponent();
        }        private void Form1_Load(object sender, EventArgs e)
        {        }        private void button1_Click(object sender, EventArgs e)
        {
            server = new TcpClient(popadr.Text, 110);//popadr是用户名textbox
            listBox1.Items.Clear();
            try
            {
                netstrm = server.GetStream();
                rdstrm = new StreamReader(server.GetStream());
                listBox1.Items.Add(rdstrm.ReadLine());                Data = "USER" + popadr.Text + CRLF;//popadr是用户名textbox
                szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArray());
                netstrm.Write(szData, 0, szData.Length);
                listBox1.Items.Add(rdstrm.ReadLine());                Data = "PASS" + password.Text + CRLF;
                szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArray());
                netstrm.Write(szData, 0, szData.Length);
                listBox1.Items.Add(rdstrm.ReadLine());                Data = "STAT" + CRLF;
                szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArray());
                netstrm.Write(szData, 0, szData.Length);
                listBox1.Items.Add(rdstrm.ReadLine());            }
            catch(Exception ex)
            {
                MessageBox.Show(ex.ToString());
            }        }
    }
}

Answer 1

网上有很多源码,搜一搜;
以前有个DEMO,一时找不到;

Answer 2

private void button1_Click(object sender, EventArgs e) 
        { 
            server = new TcpClient("pop3.163.com", 110);//popadr是用户名textbox ,这里是服务器名，不是用户名。
            listBox1.Items.Clear(); 
            try 
            { 
                netstrm = server.GetStream(); 
                rdstrm = new StreamReader(server.GetStream()); 
                listBox1.Items.Add(rdstrm.ReadLine());                 Data = "USER" + popadr.Text + CRLF;//popadr是用户名textbox 
                szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArray()); 
                netstrm.Write(szData, 0, szData.Length); 
                listBox1.Items.Add(rdstrm.ReadLine());                 Data = "PASS" + password.Text + CRLF; 
                szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArray()); 
                netstrm.Write(szData, 0, szData.Length); 
                listBox1.Items.Add(rdstrm.ReadLine());                 Data = "STAT" + CRLF; 
                szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArray()); 
                netstrm.Write(szData, 0, szData.Length); 
                listBox1.Items.Add(rdstrm.ReadLine()); 
            } 
            catch(Exception ex) 
            { 
                MessageBox.Show(ex.ToString()); 
            }         } 

Answer 3

private bool isOK()
        {            bool flag = false;
            string userName = this.txtUserName.Text.Trim();
            string passWord = this.txtPassWord.Text.Trim();
            string Data;
            byte[] szData;
            string CRLF = "\r\n";
            string pop = "pop3.163.com";
            TcpClient client = new TcpClient(pop, 110);
            try
            {
                NetworkStream stream = client.GetStream();
                StreamReader reader = new StreamReader(stream);
                Data = "USER" + userName + CRLF;
                szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArray());
                stream.Write(szData, 0, szData.Length);                             Data = "PASS" + passWord + CRLF;
                szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArray());
                stream.Write(szData, 0, szData.Length);                
               
                Data = "STAT" + CRLF;
                szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArray());
                stream.Write(szData, 0, szData.Length);                string a = reader.ReadLine();
                flag = true;            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);                
            }            return false;
        }
我写的一份，你参考下，不明白再问