using System;
using System.IO;
using System.Net;
using System.Net.Sockets;

namespace 利用POP3協(xié)議收取電子郵件
{
	/// <summary>
	/// Class1 的摘要說明。
	/// </summary>
	class Class1
	{
		/// <summary>
		/// 應(yīng)用程序的主入口點(diǎn)。
		/// </summary>
		private static  TcpClient tpServer ;
		private static byte[] byData ;
		//設(shè)定一個(gè)字節(jié)數(shù)組，用以存放向POP3服務(wù)器傳送的命令
		private static string CRLF = "\r\n" ;
		//定義回車換行符
		private static string sRec ;
		//定義一個(gè)字符串，用以存放從POP3服務(wù)器反饋數(shù)據(jù)
		private static string  sData ;
		//定義一個(gè)字符串，用以存放向POP3服務(wù)器傳送的命令字符串
		private static NetworkStream nsStream;
		private static StreamReader rdStream;
		
		[STAThread]
		static void Main(string[] args)
		{

			if ( LoadPOP ( "pop.21cn.com" , "majinhu" , "123456" ) )
			{
				sData = "RETR 1" + CRLF ;				
				//定義獲取帳戶中郵件數(shù)目和占用空間的命令
				byData = System.Text.Encoding.Default.GetBytes ( sData.ToCharArray ( ) ) ;
				nsStream.Write ( byData , 0 , byData.Length ) ;
				//向POP3服務(wù)器傳送獲取帳戶中郵件數(shù)目和占用空間的命令
				sRec = rdStream.ReadLine();
				//接收服務(wù)器反饋的數(shù)據(jù)
				/*
				以下代碼是收取帳戶中的第一封郵件，并提取數(shù)據(jù)	
				*/
				bool strBody = false ;
				string[ ] arrRet =new string[ 6 ] ;
				string[ ] arrTemp;
				if( sRec != "-" ) 
				{
					while(sRec !=".")
					{
						arrTemp = sRec.Split ( ":".ToCharArray ( ) ) ;
						if ( sRec == "" )
							strBody = true ;
						if ( arrTemp[0] == "Date" )
							arrRet[1] = arrTemp[1] ;
						if (arrTemp[0] == "From" )
							arrRet[2] = arrTemp[1] ;
						if (arrTemp[0] == "To" )
							arrRet[3] = arrTemp[1] ;
						if (arrTemp[0] == "Subject" )
							arrRet[4] = arrTemp[1] ;
						if ( strBody )
							arrRet[5] = arrRet[5] + sRec ;
						sRec = rdStream.ReadLine ( ) ;		
					}
				}
				Console.WriteLine ( "發(fā)送時(shí)間：" + arrRet[1] ) ;
				//顯示郵件發(fā)送時(shí)間信息
				Console.WriteLine ( "發(fā)送者：" + arrRet[2] ) ;
				//顯示發(fā)信人
				Console.WriteLine ( "接收者：" + arrRet[3] ) ;
				//顯示目的地址
				Console.WriteLine ( "主題：" + arrRet[4] ) ;
				//顯示郵件主題
				Console.WriteLine ( "內(nèi)容：" + arrRet[5] ) ;
			}
			//顯示郵件內(nèi)容
			//
			// TODO: 在此處添加代碼以啟動(dòng)應(yīng)用程序
			//
		}
		public static bool LoadPOP(string POPServer,string POPUser,string POPPsw)
		{
			string sPOPServer = POPServer;
			string sPOPUser = POPUser;
			string sPOPPass = POPPsw ;
			try 
			{
				tpServer = new TcpClient ( sPOPServer , 110 ) ;
				//和POP3服務(wù)器的110端口號(hào)建立TCP連接
			}
			catch 
			{
				Console.WriteLine ("無法和指定的POP3服務(wù)器建立連接！" ) ;
				return false;
			}
			nsStream = tpServer.GetStream ( ) ;
			//獲取客戶機(jī)和服務(wù)器會(huì)話的數(shù)據(jù)流
			rdStream = new StreamReader ( tpServer.GetStream ( ) ) ;
			sRec = rdStream.ReadLine ( ) ;
			sData = "USER "+ sPOPUser + CRLF ;				
			//定義向POP3服務(wù)器傳送帳戶對(duì)應(yīng)的命令行
			byData = System.Text.Encoding.Default.GetBytes ( sData.ToCharArray ( ) ) ;
			nsStream.Write ( byData , 0 , byData.Length ) ;
			//向POP3服務(wù)器傳送帳戶
			sRec = rdStream.ReadLine ( ) ;
			//接收POP3服務(wù)器反饋數(shù)據(jù)
			Console.WriteLine ( "向POP3服務(wù)器傳送帳戶后，服務(wù)器返回的信息：" + sRec ) ;
			string [ ] sUserString = sRec.Split ( " ".ToCharArray ( ) ) ;
			if ( sUserString[ 0 ] == "-ERR" )
			{
				Console.WriteLine ( "該P(yáng)OP3服務(wù)器中沒有此帳戶！" ) ;
				return false;
			}

			sData = "PASS " + sPOPPass + CRLF ;	
			//定義向POP3服務(wù)器傳送帳戶口令對(duì)應(yīng)的命令行
			byData = System.Text.Encoding.Default.GetBytes ( sData.ToCharArray ( ) ) ;
			nsStream.Write ( byData , 0 , byData.Length ) ;
			//向POP3服務(wù)器傳送帳戶對(duì)應(yīng)口令
			sRec = rdStream.ReadLine ( ) ;
			//接收POP3服務(wù)器反饋數(shù)據(jù)
			Console.WriteLine ( "向POP3服務(wù)器傳送帳戶口令后，服務(wù)器返回的信息：" + sRec ) ;
			string[ ] sPassString = sRec.Split ( " ".ToCharArray ( ) ) ;
			if ( sPassString[ 0 ] == "-ERR" )
			{
				Console.WriteLine ( "帳戶對(duì)應(yīng)的口令有誤！" ) ;
				return false;
			}
			return true;
		}


	}
}