求一个 C#接收pop3邮件的类 --顶者有分

using System;

using System.Net.Sockets;

using System.Net;

using System.Security.Cryptography;

using System.IO; 

// 类名：Pop3 

// 功能：接收电子邮件



namespace ZTSX.Email

{

/// <summary>

/// Pop3 的摘要说明。

/// </summary>

public class Pop3

{

private string mstrHost     = null; //主机名称或IP地址

private int mintPort     = 110; //主机的端口号（默认为110）

private TcpClient mtcpClient   = null; //客户端

private NetworkStream mnetStream = null; //网络基础数据流

private StreamReader m_stmReader = null; //读取字节流

private string mstrStatMessage   = null; //执行STAT命令后得到的消息（从中得到邮件数）



/// <summary>

/// 构造函数

/// </summary>

/// <remarks>一个邮件接收对象</remarks>

public Pop3()

{

}



/// <summary>

/// 构造函数

/// </summary>

/// <param name="host">主机名称或IP地址</param>

public Pop3(string host)

{

   mstrHost = host;

}



/// <summary>

/// 构造函数

/// </summary>

/// <param name="host">主机名称或IP地址</param>

/// <param name="port">主机的端口号</param>

/// <remarks>一个邮件接收对象</remarks>

public Pop3(string host,int port)

{

   mstrHost = host;

   mintPort = port;

}



#region 属性



/// <summary>

/// 主机名称或IP地址

/// </summary>

/// <remarks>主机名称或IP地址</remarks>

public string HostName

{

   get{return mstrHost;}

   set{mstrHost = value;}

}



/// <summary>

/// 主机的端口号

/// </summary>

/// <remarks>主机的端口号</remarks>

public int Port

{

   get{return mintPort;}

   set{mintPort = value;}

}



#endregion



#region 私有方法



/// <summary>

/// 向网络访问的基础数据流中写数据（发送命令码）

/// </summary>

/// <param name="netStream">可以用于网络访问的基础数据流</param>

/// <param name="command">命令行</param>

/// <remarks>向网络访问的基础数据流中写数据（发送命令码）</remarks>

private void WriteToNetStream(ref NetworkStream netStream,String command)

{

   string strToSend = command + "\r\n";

   byte[] arrayToSend = System.Text.Encoding.ASCII.GetBytes(strToSend.ToCharArray());

      netStream.Write(arrayToSend,0,arrayToSend.Length);

}



/// <summary>

/// 检查命令行结果是否正确

/// </summary>

/// <param name="message">命令行的执行结果</param>

/// <param name="check">正确标志</param>

/// <returns>

/// 类型：布尔

/// 内容：true表示没有错误，false为有错误

/// </returns>

/// <remarks>检查命令行结果是否有错误</remarks>

private bool CheckCorrect(string message,string check)

{

   if(message.IndexOf(check) == -1)

    return false;

   else

    return true;

}



/// <summary>

/// 邮箱中的未读邮件数

/// </summary>

/// <param name="message">执行完LIST命令后的结果</param>

/// <returns>

/// 类型：整型

/// 内容：邮箱中的未读邮件数

/// </returns>

/// <remarks>邮箱中的未读邮件数</remarks>

private int GetMailNumber(string message)

{

   string[] strMessage = message.Split(' ');

   return Int32.Parse(strMessage[1]);

}



/// <summary>

/// 得到经过解码后的邮件的内容

/// </summary>

/// <param name="encodingContent">解码前的邮件的内容</param>

/// <returns>

/// 类型：字符串

/// 内容：解码后的邮件的内容

/// </returns>

/// <remarks>得到解码后的邮件的内容</remarks>

private string GetDecodeMailContent(string encodingContent)

{

   string strContent = encodingContent.Trim();

   string strEncode = null;



   int iStart = strContent.IndexOf("Base64");

   if(iStart == -1)

    throw new Pop3Exception("邮件内容不是Base64编码，请检查");

   else

   {

    strEncode = strContent.Substring(iStart + 6,strContent.Length - iStart - 6);

    try

    {

     return SX.Encode.TransformToString(strEncode);

    }

    catch(SX.EncodeException exc)

    {

     throw new Pop3Exception(exc.Message);

    }

   }

}



#endregion



/// <summary>

/// 与主机建立连接

/// </summary>

/// <returns>

/// 类型：布尔

/// 内容：连接结果（true为连接成功，false为连接失败）

/// </returns>

/// <remarks>与主机建立连接</remarks>

public bool Connect()

{

   if(mstrHost == null)

    throw new Exception("请提供SMTP主机名称或IP地址！");

   if(mintPort == 0)

    throw new Exception("请提供SMTP主机的端口号");

   try

   {

    mtcpClient = new TcpClient(mstrHost,mintPort);

    mnetStream = mtcpClient.GetStream();

    m_stmReader = new StreamReader(mtcpClient.GetStream());



    string strMessage = m_stmReader.ReadLine();

    if(CheckCorrect(strMessage,"+OK") == true)

     return true;

    else

     return false;

   }

   catch(SocketException exc)

   {

    throw new Pop3Exception(exc.ToString());

   }

   catch(NullReferenceException exc)

   {

    throw new Pop3Exception(exc.ToString());

   }

}



#region Pop3命令



/// <summary>

/// 执行Pop3命令，并检查执行的结果

/// </summary>

/// <param name="command">Pop3命令行</param>

/// <returns>

/// 类型：字符串

/// 内容：Pop3命令的执行结果

/// </returns>

private string ExecuteCommand(string command)

{

   string strMessage = null; //执行Pop3命令后返回的消息



   try

   {

    //发送命令

    WriteToNetStream(ref mnetStream,command);



    //读取多行

    if(command.Substring(0,4).Equals("LIST") || command.Substring(0,4).Equals("RETR") || command.Substring(0,4).Equals("UIDL")) //记录STAT后的消息（其中包含邮件数）

    {

     strMessage = ReadMultiLine();



     if(command.Equals("LIST")) //记录LIST后的消息（其中包含邮件数）

      mstrStatMessage = strMessage;

    }

     //读取单行

    else

     strMessage = m_stmReader.ReadLine();



    //判断执行结果是否正确

    if(CheckCorrect(strMessage,"+OK"))

     return strMessage;

    else

     return "Error";

   }

   catch(IOException exc)

   {

    throw new Pop3Exception(exc.ToString());

   }

}



/// <summary>

/// 在Pop3命令中，LIST、RETR和UIDL命令的结果要返回多行，以点号（.）结尾，

/// 所以如果想得到正确的结果，必须读取多行

/// </summary>

/// <returns>

/// 类型：字符串

/// 内容：执行Pop3命令后的结果

/// </returns>

private string ReadMultiLine()

{

   string strMessage = m_stmReader.ReadLine();

   string strTemp = null;

   while(strMessage != ".")

   {

    strTemp = strTemp + strMessage;

    strMessage = m_stmReader.ReadLine();

   }

   return strTemp;

}



//USER命令

private string USER(string user)

{

   return ExecuteCommand("USER " + user) + "\r\n";

}



//PASS命令

private string PASS(string password)

{

   return ExecuteCommand("PASS " + password) + "\r\n";

}



//LIST命令

private string LIST()

{

   return ExecuteCommand("LIST") + "\r\n";

}



//UIDL命令

private string UIDL()

{

   return ExecuteCommand("UIDL") + "\r\n";

}



//NOOP命令

private string NOOP()

{

   return ExecuteCommand("NOOP") + "\r\n";

}



//STAT命令

private string STAT()

{

   return ExecuteCommand("STAT") + "\r\n";

}



//RETR命令

private string RETR(int number)

{

   return ExecuteCommand("RETR " + number.ToString()) + "\r\n";

}



//DELE命令

private string DELE(int number)

{

   return ExecuteCommand("DELE " + number.ToString()) + "\r\n";

}



//QUIT命令

private void Quit()

{

   WriteToNetStream(ref mnetStream,"QUIT");

}



/// <summary>

/// 收取邮件

/// </summary>

/// <param name="user">用户名</param>

/// <param name="password">口令</param>

/// <returns>

/// 类型：字符串数组

/// 内容：解码前的邮件内容

/// </returns>

private string[] ReceiveMail(string user,string password)

{

   int iMailNumber = 0; //邮件数



   if(USER(user).Equals("Error"))

    throw new Pop3Exception("用户名不正确！");

   if(PASS(password).Equals("Error"))

    throw new Pop3Exception("用户口令不正确！");

   if(STAT().Equals("Error"))

    throw new Pop3Exception("准备接收邮件时发生错误！");

   if(LIST().Equals("Error"))

    throw new Pop3Exception("得到邮件列表时发生错误！");



   try

   {

    iMailNumber = GetMailNumber(mstrStatMessage);



    //没有新邮件

    if(iMailNumber == 0)

     return null;

    else

    {

     string[] strMailContent = new string[iMailNumber];



     for(int i = 1 ; i <= iMailNumber ; i++)

     {

      //读取邮件内容

      strMailContent[i - 1] = GetDecodeMailContent(RETR(i));

     }

     return strMailContent;

    }

   }

   catch(Pop3Exception exc)

   {

    throw new Pop3Exception(exc.ToString());

   }

}



#endregion





/// <summary>

/// 收取邮件     

/// </summary>

/// <param name="user">用户名</param>

/// <param name="password">口令</param>

/// <returns>

/// 类型：字符串数组

/// 内容：解码前的邮件内容

/// </returns>

///<remarks>收取邮箱中的未读邮件</remarks>

public string[] Receive(string user,string password)

{

   try

   {

    return ReceiveMail(user,password);

   }

   catch(Pop3Exception exc)

   {

    throw new Pop3Exception(exc.ToString());

   }

}



/// <summary>

/// 断开所有与服务器的会话

/// </summary>

/// <remarks>断开所有与服务器的会话</remarks>

public void DisConnect()

{

   try

   {

    Quit();

    if(m_stmReader != null)

     m_stmReader.Close();

    if(mnetStream != null)

     mnetStream.Close();

    if(mtcpClient != null)

     mtcpClient.Close();

   }

   catch(SocketException exc)

   {

    throw new Pop3Exception(exc.ToString());

   }

}



/// <summary>

/// 删除邮件

/// </summary>

/// <param name="number">邮件号</param>

public void DeleteMail(int number)

{

   //删除邮件

   int iMailNumber = number + 1;

   if(DELE(iMailNumber).Equals("Error"))

    throw new Pop3Exception("删除第" + iMailNumber.ToString() + "时出现错误！");

}



}

}