在vs3下调试无误的pop3收信程序

using System.Net.Sockets;
using System.Collections;
using System.IO;
using System.Net;
using System;
using System.Web.Mail;

public class POP3
{
    string POPServer;
    string user;
    string pwd;
    NetworkStream ns;
    StreamReader sr;

    public POP3(){}

    public POP3(string server, string _user, string _pwd)
    {
        POPServer = server;
        user = _user;
        pwd = _pwd;
    }

    private void Connect()
    {
        TcpClient sender = new TcpClient(POPServer,110);
        Byte[] outbytes;
        string input;

        try
        {
            ns = sender.GetStream();
            sr = new StreamReader(ns);

            sr.ReadLine();
            //Console.WriteLine(sr.ReadLine() );

            input = "user " + user + " ";
            outbytes = System.Text.Encoding.ASCII.GetBytes(input.ToCharArray());
            ns.Write(outbytes,0,outbytes.Length) ;
            sr.ReadLine();
            //Console.WriteLine(sr.ReadLine() );

            input = "pass " + pwd + " ";
            outbytes = System.Text.Encoding.ASCII.GetBytes(input.ToCharArray());
            ns.Write(outbytes,0,outbytes.Length) ;
            sr.ReadLine();
            //Console.WriteLine(sr.ReadLine() );

        }
        catch(InvalidOperationException ioe)
        {
            Console.WriteLine("Could not connect to mail server");
        }
    }

    private void Disconnect()
    {
        string input = "quit" + " ";
        Byte[] outbytes = System.Text.Encoding.ASCII.GetBytes(input.ToCharArray());
        ns.Write(outbytes,0,outbytes.Length);
        //Console.WriteLine(sr.ReadLine() );
        ns.Close();
    }

    public int GetNumberOfNewMessages()
    {
        Byte[] outbytes;
        string input;

        try
        {
            Connect();

            input = "stat" + " ";
            outbytes = System.Text.Encoding.ASCII.GetBytes(input.ToCharArray());
            ns.Write(outbytes,0,outbytes.Length);
            string resp = sr.ReadLine();
            //Console.WriteLine(resp);
            string[] tokens = resp.Split(new Char[] {@# @#});

            Disconnect();

            return Convert.ToInt32(tokens[1]);
        }
        catch(InvalidOperationException ioe)
        {
            Console.WriteLine("Could not connect to mail server");
            return 0;
        }
    }
    public ArrayList GetNewMessages(string subj)
    {

        int newcount;
        ArrayList newmsgs = new ArrayList();

        try
        {
            newcount = GetNumberOfNewMessages();
            Connect();
    
            for(int n=1; n<newcount+1; n++)
            {
                ArrayList msglines = GetRawMessage(n);
                string msgsubj = GetMessageSubject(msglines);
                if(msgsubj.CompareTo(subj) == 0)
                {
                    System.Web.Mail.MailMessage msg = new MailMessage();
                    msg.Subject = msgsubj;
                    msg.From = GetMessageFrom(msglines);
                    msg.Body = GetMessageBody(msglines);
                    newmsgs.Add(msg);
                    DeleteMessage(n);
                }
            }

            Disconnect();
            return newmsgs;
        }
        catch(Exception e)
        {
            Console.WriteLine(e.ToString() );
            Console.ReadLine();
            return newmsgs;
        }
    }
    private ArrayList GetRawMessage (int messagenumber)
    {
        Byte[] outbytes;
        string input;
        string line = "";

        input = "retr " + messagenumber.ToString() + " ";
        outbytes = System.Text.Encoding.ASCII.GetBytes(input.ToCharArray());
        ns.Write(outbytes,0,outbytes.Length);
    
        ArrayList msglines = new ArrayList();
        do
        {
            line = sr.ReadLine();
            msglines.Add(line);
        } while (line != ".");
        msglines.RemoveAt(msglines.Count-1);

        return msglines;
    }
    private string GetMessageSubject(ArrayList msglines)
    {
        string[] tokens;
        IEnumerator msgenum = msglines.GetEnumerator();
        while (msgenum.MoveNext() )
        {
            string line = (string)msgenum.Current;
            if(line.StartsWith("Subject:") )
            {
                tokens = line.Split(new Char[] {@# @#});
                return tokens[1].Trim();
            }
        }
        return "None";
    }
    private string GetMessageFrom (ArrayList msglines)
    {
        string[] tokens;
        IEnumerator msgenum = msglines.GetEnumerator();
        while (msgenum.MoveNext() )
        {
            string line = (string)msgenum.Current;
            if(line.StartsWith("Return-Path:") )
            {
                tokens = line.Split(new Char[] {@#<@#});
                return tokens[1].Trim(new Char[] {@#<@#,@#>@#});
            }
        }
        return "None";
    }
    private string GetMessageBody(ArrayList msglines)
    {
        string body = "";
        string line = " ";
        IEnumerator msgenum = msglines.GetEnumerator();
    
        while(line.CompareTo("") != 0)
        {
            msgenum.MoveNext();
            line = (string)msgenum.Current;
        }

        while (msgenum.MoveNext() )
        {
            body = body + (string)msgenum.Current + " ";
        }
        return body;
    }
    private void DeleteMessage(int messagenumber)
    {
        Byte[] outbytes;
        string input;

        try
        {
            input = "dele " + messagenumber.ToString() + " ";
            outbytes = System.Text.Encoding.ASCII.GetBytes(input.ToCharArray());
            ns.Write(outbytes,0,outbytes.Length);
        }
        catch(Exception e)
        {
            Console.WriteLine(e.ToString() );
            Console.ReadLine();
        }
    
    }

}

原文转自：http://www.ltesting.net