分享用于操作FTP的客户端C#类

这是一个用于操作FTP的客户端C#类，类已经封装好了各种常用的Ftp操作方法，调用非常简单，你不需要关心ftp连接和操作的细节，只要调用这个类里的相关方法就可以了。

using System;
using System.Net;
using System.IO;
using System.Text;
using System.Net.Sockets;
using System.Threading;
 
namespace DotNet.Utilities
{
  public class FTPClient
  {
    public static object obj = new object();
 
    #region 构造函数
    /// <summary>
    /// 缺省构造函数
    /// </summary>
    public FTPClient()
    {
      strRemoteHost = "";
      strRemotePath = "";
      strRemoteUser = "";
      strRemotePass = "";
      strRemotePort = 21;
      bConnected = false;
    }
 
    /// <summary>
    /// 构造函数
    /// </summary>
    public FTPClient(string remoteHost, string remotePath, string remoteUser, string remotePass, int remotePort)
    {
      strRemoteHost = remoteHost;
      strRemotePath = remotePath;
      strRemoteUser = remoteUser;
      strRemotePass = remotePass;
      strRemotePort = remotePort;
      Connect();
    }
    #endregion
 
    #region 字段
    private int strRemotePort;
    private Boolean bConnected;
    private string strRemoteHost;
    private string strRemotePass;
    private string strRemoteUser;
    private string strRemotePath;
 
    /// <summary>
    /// 服务器返回的应答信息(包含应答码)
    /// </summary>
    private string strMsg;
    /// <summary>
    /// 服务器返回的应答信息(包含应答码)
    /// </summary>
    private string strReply;
    /// <summary>
    /// 服务器返回的应答码
    /// </summary>
    private int iReplyCode;
    /// <summary>
    /// 进行控制连接的socket
    /// </summary>
    private Socket socketControl;
    /// <summary>
    /// 传输模式
    /// </summary>
    private TransferType trType;
    /// <summary>
    /// 接收和发送数据的缓冲区
    /// </summary>
    private static int BLOCK_SIZE = 512;
    /// <summary>
    /// 编码方式
    /// </summary>
    Encoding ASCII = Encoding.ASCII;
    /// <summary>
    /// 字节数组
    /// </summary>
    Byte[] buffer = new Byte[BLOCK_SIZE];
    #endregion
 
    #region 属性
    /// <summary>
    /// FTP服务器IP地址
    /// </summary>
    public string RemoteHost
    {
      get
      {
        return strRemoteHost;
      }
      set
      {
        strRemoteHost = value;
      }
    }
 
    /// <summary>
    /// FTP服务器端口
    /// </summary>
    public int RemotePort
    {
      get
      {
        return strRemotePort;
      }
      set
      {
        strRemotePort = value;
      }
    }
 
    /// <summary>
    /// 当前服务器目录
    /// </summary>
    public string RemotePath
    {
      get
      {
        return strRemotePath;
      }
      set
      {
        strRemotePath = value;
      }
    }
 
    /// <summary>
    /// 登录用户账号
    /// </summary>
    public string RemoteUser
    {
      set
      {
        strRemoteUser = value;
      }
    }
 
    /// <summary>
    /// 用户登录密码
    /// </summary>
    public string RemotePass
    {
      set
      {
        strRemotePass = value;
      }
    }
 
    /// <summary>
    /// 是否登录
    /// </summary>
    public bool Connected
    {
      get
      {
        return bConnected;
      }
    }
    #endregion
 
    #region 链接
    /// <summary>
    /// 建立连接
    /// </summary>
    public void Connect()
    {
      lock (obj)
      {
        socketControl = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        IPEndPoint ep = new IPEndPoint(IPAddress.Parse(RemoteHost), strRemotePort);
        try
        {
          socketControl.Connect(ep);
        }
        catch (Exception)
        {
          throw new IOException("不能连接ftp服务器");
        }
      }
      ReadReply();
      if (iReplyCode != 220)
      {
        DisConnect();
        throw new IOException(strReply.Substring(4));
      }
      SendCommand("USER " + strRemoteUser);
      if (!(iReplyCode == 331 || iReplyCode == 230))
      {
        CloseSocketConnect();
        throw new IOException(strReply.Substring(4));
      }
      if (iReplyCode != 230)
      {
        SendCommand("PASS " + strRemotePass);
        if (!(iReplyCode == 230 || iReplyCode == 202))
        {
          CloseSocketConnect();
          throw new IOException(strReply.Substring(4));
        }
      }
      bConnected = true;
      ChDir(strRemotePath);
    }
 
    /// <summary>
    /// 关闭连接
    /// </summary>
    public void DisConnect()
    {
      if (socketControl != null)
      {
        SendCommand("QUIT");
      }
      CloseSocketConnect();
    }
    #endregion
 
    #region 传输模式
    /// <summary>
    /// 传输模式:二进制类型、ASCII类型
    /// </summary>
    public enum TransferType { Binary, ASCII };
 
    /// <summary>
    /// 设置传输模式
    /// </summary>
    /// <param name="ttType">传输模式</param>
    public void SetTransferType(TransferType ttType)
    {
      if (ttType == TransferType.Binary)
      {
        SendCommand("TYPE I");//binary类型传输
      }
      else
      {
        SendCommand("TYPE A");//ASCII类型传输
      }
      if (iReplyCode != 200)
      {
        throw new IOException(strReply.Substring(4));
      }
      else
      {
        trType = ttType;
      }
    }
 
    /// <summary>
    /// 获得传输模式
    /// </summary>
    /// <returns>传输模式</returns>
    public TransferType GetTransferType()
    {
      return trType;
    }
    #endregion
 
    #region 文件操作
    /// <summary>
    /// 获得文件列表
    /// </summary>
    /// <param name="strMask">文件名的匹配字符串</param>
    public string[] Dir(string strMask)
    {
      if (!bConnected)
      {
        Connect();
      }
      Socket socketData = CreateDataSocket();
      SendCommand("NLST " + strMask);
      if (!(iReplyCode == 150 || iReplyCode == 125 || iReplyCode == 226))
      {
        throw new IOException(strReply.Substring(4));
      }
      strMsg = "";
      Thread.Sleep(2000);
      while (true)
      {
        int iBytes = socketData.Receive(buffer, buffer.Length, 0);
        strMsg += ASCII.GetString(buffer, 0, iBytes);
        if (iBytes < buffer.Length)
        {
          break;
        }
      }
      char[] seperator = { '\n' };
      string[] strsFileList = strMsg.Split(seperator);
      socketData.Close(); //数据socket关闭时也会有返回码
      if (iReplyCode != 226)
      {
        ReadReply();
        if (iReplyCode != 226)
        {
 
          throw new IOException(strReply.Substring(4));
        }
      }
      return strsFileList;
    }
 
    public void newPutByGuid(string strFileName, string strGuid)
    {
      if (!bConnected)
      {
        Connect();
      }
      string str = strFileName.Substring(0, strFileName.LastIndexOf("\\"));
      string strTypeName = strFileName.Substring(strFileName.LastIndexOf("."));
      strGuid = str + "\\" + strGuid;
      Socket socketData = CreateDataSocket();
      SendCommand("STOR " + Path.GetFileName(strGuid));
      if (!(iReplyCode == 125 || iReplyCode == 150))
      {
        throw new IOException(strReply.Substring(4));
      }
      FileStream input = new FileStream(strGuid, FileMode.Open);
      input.Flush();
      int iBytes = 0;
      while ((iBytes = input.Read(buffer, 0, buffer.Length)) > 0)
      {
        socketData.Send(buffer, iBytes, 0);
      }
      input.Close();
      if (socketData.Connected)
      {
        socketData.Close();
      }
      if (!(iReplyCode == 226 || iReplyCode == 250))
      {
        ReadReply();
        if (!(iReplyCode == 226 || iReplyCode == 250))
        {
          throw new IOException(strReply.Substring(4));
        }
      }
    }
 
    /// <summary>
    /// 获取文件大小
    /// </summary>
    /// <param name="strFileName">文件名</param>
    /// <returns>文件大小</returns>
    public long GetFileSize(string strFileName)
    {
      if (!bConnected)
      {
        Connect();
      }
      SendCommand("SIZE " + Path.GetFileName(strFileName));
      long lSize = 0;
      if (iReplyCode == 213)
      {
        lSize = Int64.Parse(strReply.Substring(4));
      }
      else
      {
        throw new IOException(strReply.Substring(4));
      }
      return lSize;
    }
 
 
    /// <summary>
    /// 获取文件信息
    /// </summary>
    /// <param name="strFileName">文件名</param>
    /// <returns>文件大小</returns>
    public string GetFileInfo(string strFileName)
    {
      if (!bConnected)
      {
        Connect();
      }
      Socket socketData = CreateDataSocket();
      SendCommand("LIST " + strFileName);
      string strResult = "";
      if (!(iReplyCode == 150 || iReplyCode == 125
        || iReplyCode == 226 || iReplyCode == 250))
      {
        throw new IOException(strReply.Substring(4));
      }
      byte[] b = new byte[512];
      MemoryStream ms = new MemoryStream();
 
      while (true)
      {
        int iBytes = socketData.Receive(b, b.Length, 0);
        ms.Write(b, 0, iBytes);
        if (iBytes <= 0)
        {
 
          break;
        }
      }
      byte[] bt = ms.GetBuffer();
      strResult = System.Text.Encoding.ASCII.GetString(bt);
      ms.Close();
      return strResult;
    }
 
    /// <summary>
    /// 删除
    /// </summary>
    /// <param name="strFileName">待删除文件名</param>
    public void Delete(string strFileName)
    {
      if (!bConnected)
      {
        Connect();
      }
      SendCommand("DELE " + strFileName);
      if (iReplyCode != 250)
      {
        throw new IOException(strReply.Substring(4));
      }
    }
 
    /// <summary>
    /// 重命名(如果新文件名与已有文件重名,将覆盖已有文件)
    /// </summary>
    /// <param name="strOldFileName">旧文件名</param>
    /// <param name="strNewFileName">新文件名</param>
    public void Rename(string strOldFileName, string strNewFileName)
    {
      if (!bConnected)
      {
        Connect();
      }
      SendCommand("RNFR " + strOldFileName);
      if (iReplyCode != 350)
      {
        throw new IOException(strReply.Substring(4));
      }
      // 如果新文件名与原有文件重名,将覆盖原有文件
      SendCommand("RNTO " + strNewFileName);
      if (iReplyCode != 250)
      {
        throw new IOException(strReply.Substring(4));
      }
    }
    #endregion
 
    #region 上传和下载
    /// <summary>
    /// 下载一批文件
    /// </summary>
    /// <param name="strFileNameMask">文件名的匹配字符串</param>
    /// <param name="strFolder">本地目录(不得以\结束)</param>
    public void Get(string strFileNameMask, string strFolder)
    {
      if (!bConnected)
      {
        Connect();
      }
      string[] strFiles = Dir(strFileNameMask);
      foreach (string strFile in strFiles)
      {
        if (!strFile.Equals(""))//一般来说strFiles的最后一个元素可能是空字符串
        {
          Get(strFile, strFolder, strFile);
        }
      }
    }
 
    /// <summary>
    /// 下载一个文件
    /// </summary>
    /// <param name="strRemoteFileName">要下载的文件名</param>
    /// <param name="strFolder">本地目录(不得以\结束)</param>
    /// <param name="strLocalFileName">保存在本地时的文件名</param>
    public void Get(string strRemoteFileName, string strFolder, string strLocalFileName)
    {
      Socket socketData = CreateDataSocket();
      try
      {
        if (!bConnected)
        {
          Connect();
        }
        SetTransferType(TransferType.Binary);
        if (strLocalFileName.Equals(""))
        {
          strLocalFileName = strRemoteFileName;
        }
        SendCommand("RETR " + strRemoteFileName);
        if (!(iReplyCode == 150 || iReplyCode == 125 || iReplyCode == 226 || iReplyCode == 250))
        {
          throw new IOException(strReply.Substring(4));
        }
        FileStream output = new FileStream(strFolder + "\\" + strLocalFileName, FileMode.Create);
        while (true)
        {
          int iBytes = socketData.Receive(buffer, buffer.Length, 0);
          output.Write(buffer, 0, iBytes);
          if (iBytes <= 0)
          {
            break;
          }
        }
        output.Close();
        if (socketData.Connected)
        {
          socketData.Close();
        }
        if (!(iReplyCode == 226 || iReplyCode == 250))
        {
          ReadReply();
          if (!(iReplyCode == 226 || iReplyCode == 250))
          {
            throw new IOException(strReply.Substring(4));
          }
        }
      }
      catch
      {
        socketData.Close();
        socketData = null;
        socketControl.Close();
        bConnected = false;
        socketControl = null;
      }
    }
 
    /// <summary>
    /// 下载一个文件
    /// </summary>
    /// <param name="strRemoteFileName">要下载的文件名</param>
    /// <param name="strFolder">本地目录(不得以\结束)</param>
    /// <param name="strLocalFileName">保存在本地时的文件名</param>
    public void GetNoBinary(string strRemoteFileName, string strFolder, string strLocalFileName)
    {
      if (!bConnected)
      {
        Connect();
      }
 
      if (strLocalFileName.Equals(""))
      {
        strLocalFileName = strRemoteFileName;
      }
      Socket socketData = CreateDataSocket();
      SendCommand("RETR " + strRemoteFileName);
      if (!(iReplyCode == 150 || iReplyCode == 125 || iReplyCode == 226 || iReplyCode == 250))
      {
        throw new IOException(strReply.Substring(4));
      }
      FileStream output = new FileStream(strFolder + "\\" + strLocalFileName, FileMode.Create);
      while (true)
      {
        int iBytes = socketData.Receive(buffer, buffer.Length, 0);
        output.Write(buffer, 0, iBytes);
        if (iBytes <= 0)
        {
          break;
        }
      }
      output.Close();
      if (socketData.Connected)
      {
        socketData.Close();
      }
      if (!(iReplyCode == 226 || iReplyCode == 250))
      {
        ReadReply();
        if (!(iReplyCode == 226 || iReplyCode == 250))
        {
          throw new IOException(strReply.Substring(4));
        }
      }
    }
 
    /// <summary>
    /// 上传一批文件
    /// </summary>
    /// <param name="strFolder">本地目录(不得以\结束)</param>
    /// <param name="strFileNameMask">文件名匹配字符(可以包含*和?)</param>
    public void Put(string strFolder, string strFileNameMask)
    {
      string[] strFiles = Directory.GetFiles(strFolder, strFileNameMask);
      foreach (string strFile in strFiles)
      {
        Put(strFile);
      }
    }
 
    /// <summary>
    /// 上传一个文件
    /// </summary>
    /// <param name="strFileName">本地文件名</param>
    public void Put(string strFileName)
    {
      if (!bConnected)
      {
        Connect();
      }
      Socket socketData = CreateDataSocket();
      if (Path.GetExtension(strFileName) == "")
        SendCommand("STOR " + Path.GetFileNameWithoutExtension(strFileName));
      else
        SendCommand("STOR " + Path.GetFileName(strFileName));
 
      if (!(iReplyCode == 125 || iReplyCode == 150))
      {
        throw new IOException(strReply.Substring(4));
      }
 
      FileStream input = new FileStream(strFileName, FileMode.Open);
      int iBytes = 0;
      while ((iBytes = input.Read(buffer, 0, buffer.Length)) > 0)
      {
        socketData.Send(buffer, iBytes, 0);
      }
      input.Close();
      if (socketData.Connected)
      {
        socketData.Close();
      }
      if (!(iReplyCode == 226 || iReplyCode == 250))
      {
        ReadReply();
        if (!(iReplyCode == 226 || iReplyCode == 250))
        {
          throw new IOException(strReply.Substring(4));
        }
      }
    }
 
 
    /// <summary>
    /// 上传一个文件
    /// </summary>
    /// <param name="strFileName">本地文件名</param>
    public void PutByGuid(string strFileName, string strGuid)
    {
      if (!bConnected)
      {
        Connect();
      }
      string str = strFileName.Substring(0, strFileName.LastIndexOf("\\"));
      string strTypeName = strFileName.Substring(strFileName.LastIndexOf("."));
      strGuid = str + "\\" + strGuid;
      System.IO.File.Copy(strFileName, strGuid);
      System.IO.File.SetAttributes(strGuid, System.IO.FileAttributes.Normal);
      Socket socketData = CreateDataSocket();
      SendCommand("STOR " + Path.GetFileName(strGuid));
      if (!(iReplyCode == 125 || iReplyCode == 150))
      {
        throw new IOException(strReply.Substring(4));
      }
      FileStream input = new FileStream(strGuid, FileMode.Open, System.IO.FileAccess.Read, System.IO.FileShare.Read);
      int iBytes = 0;
      while ((iBytes = input.Read(buffer, 0, buffer.Length)) > 0)
      {
        socketData.Send(buffer, iBytes, 0);
      }
      input.Close();
      File.Delete(strGuid);
      if (socketData.Connected)
      {
        socketData.Close();
      }
      if (!(iReplyCode == 226 || iReplyCode == 250))
      {
        ReadReply();
        if (!(iReplyCode == 226 || iReplyCode == 250))
        {
          throw new IOException(strReply.Substring(4));
        }
      }
    }
    #endregion
 
    #region 目录操作
    /// <summary>
    /// 创建目录
    /// </summary>
    /// <param name="strDirName">目录名</param>
    public void MkDir(string strDirName)
    {
      if (!bConnected)
      {
        Connect();
      }
      SendCommand("MKD " + strDirName);
      if (iReplyCode != 257)
      {
        throw new IOException(strReply.Substring(4));
      }
    }
 
    /// <summary>
    /// 删除目录
    /// </summary>
    /// <param name="strDirName">目录名</param>
    public void RmDir(string strDirName)
    {
      if (!bConnected)
      {
        Connect();
      }
      SendCommand("RMD " + strDirName);
      if (iReplyCode != 250)
      {
        throw new IOException(strReply.Substring(4));
      }
    }
 
    /// <summary>
    /// 改变目录
    /// </summary>
    /// <param name="strDirName">新的工作目录名</param>
    public void ChDir(string strDirName)
    {
      if (strDirName.Equals(".") || strDirName.Equals(""))
      {
        return;
      }
      if (!bConnected)
      {
        Connect();
      }
      SendCommand("CWD " + strDirName);
      if (iReplyCode != 250)
      {
        throw new IOException(strReply.Substring(4));
      }
      this.strRemotePath = strDirName;
    }
    #endregion
 
    #region 内部函数
    /// <summary>
    /// 将一行应答字符串记录在strReply和strMsg,应答码记录在iReplyCode
    /// </summary>
    private void ReadReply()
    {
      strMsg = "";
      strReply = ReadLine();
      iReplyCode = Int32.Parse(strReply.Substring(0, 3));
    }
 
    /// <summary>
    /// 建立进行数据连接的socket
    /// </summary>
    /// <returns>数据连接socket</returns>
    private Socket CreateDataSocket()
    {
      SendCommand("PASV");
      if (iReplyCode != 227)
      {
        throw new IOException(strReply.Substring(4));
      }
      int index1 = strReply.IndexOf('(');
      int index2 = strReply.IndexOf(')');
      string ipData = strReply.Substring(index1 + 1, index2 - index1 - 1);
      int[] parts = new int[6];
      int len = ipData.Length;
      int partCount = 0;
      string buf = "";
      for (int i = 0; i < len && partCount <= 6; i++)
      {
        char ch = Char.Parse(ipData.Substring(i, 1));
        if (Char.IsDigit(ch))
          buf += ch;
        else if (ch != ',')
        {
          throw new IOException("Malformed PASV strReply: " + strReply);
        }
        if (ch == ',' || i + 1 == len)
        {
          try
          {
            parts[partCount++] = Int32.Parse(buf);
            buf = "";
          }
          catch (Exception)
          {
            throw new IOException("Malformed PASV strReply: " + strReply);
          }
        }
      }
      string ipAddress = parts[0] + "." + parts[1] + "." + parts[2] + "." + parts[3];
      int port = (parts[4] << 8) + parts[5];
      Socket s = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
      IPEndPoint ep = new IPEndPoint(IPAddress.Parse(ipAddress), port);
      try
      {
        s.Connect(ep);
      }
      catch (Exception)
      {
        throw new IOException("无法连接ftp服务器");
      }
      return s;
    }
 
    /// <summary>
    /// 关闭socket连接(用于登录以前)
    /// </summary>
    private void CloseSocketConnect()
    {
      lock (obj)
      {
        if (socketControl != null)
        {
          socketControl.Close();
          socketControl = null;
        }
        bConnected = false;
      }
    }
 
    /// <summary>
    /// 读取Socket返回的所有字符串
    /// </summary>
    /// <returns>包含应答码的字符串行</returns>
    private string ReadLine()
    {
      lock (obj)
      {
        while (true)
        {
          int iBytes = socketControl.Receive(buffer, buffer.Length, 0);
          strMsg += ASCII.GetString(buffer, 0, iBytes);
          if (iBytes < buffer.Length)
          {
            break;
          }
        }
      }
      char[] seperator = { '\n' };
      string[] mess = strMsg.Split(seperator);
      if (strMsg.Length > 2)
      {
        strMsg = mess[mess.Length - 2];
      }
      else
      {
        strMsg = mess[0];
      }
      if (!strMsg.Substring(3, 1).Equals(" ")) //返回字符串正确的是以应答码(如220开头,后面接一空格,再接问候字符串)
      {
        return ReadLine();
      }
      return strMsg;
    }
 
    /// <summary>
    /// 发送命令并获取应答码和最后一行应答字符串
    /// </summary>
    /// <param name="strCommand">命令</param>
    public void SendCommand(String strCommand)
    {
      lock (obj)
      {
        Byte[] cmdBytes = Encoding.ASCII.GetBytes((strCommand + "\r\n").ToCharArray());
        socketControl.Send(cmdBytes, cmdBytes.Length, 0);
        Thread.Sleep(500);
        ReadReply();
      }
    }
    #endregion
  }
}

方法二：

using System;
using System.Net;
using System.IO;
using System.Text;
using System.Net.Sockets;
namespace FtpLib
{
public class FTPFactory
{
  private string
  remoteHost, remotePath, remoteUser, remotePass, mes;
  private int remotePort, bytes;
  private Socket clientSocket;
  private int retValue;
  private Boolean debug;
  private Boolean logined;
  private string reply;
  private static int BLOCK_SIZE = 512;
  Byte[] buffer = new Byte[BLOCK_SIZE];
  Encoding ASCII = Encoding.ASCII;
  public FTPFactory()
  {
    remoteHost = "localhost";
    remotePath = ".";
    remoteUser = "anonymous";
    remotePass = "";
    remotePort = 21;
    debug = false;
    logined = false;
  }
  ///

  /// Set the name of the FTP server to connect to.

  ///

  /// Server name

  public void setRemoteHost(string remoteHost)
  {
    this.remoteHost = remoteHost;
  }
  ///

  /// Return the name of the current FTP server.

  ///

  /// Server name

  public string getRemoteHost()
  {
    return remoteHost;
  }
  ///

  /// Set the port number to use for FTP.

  ///

  /// Port number

  public void setRemotePort(int remotePort)
  {
    this.remotePort = remotePort;
  }
  ///

  /// Return the current port number.

  ///

  /// Current port number

  public int getRemotePort()
  {
    return remotePort;
  }
  ///

  /// Set the remote directory path.

  ///

  /// The remote directory path

  public void setRemotePath(string remotePath)
  {
    this.remotePath = remotePath;
  }
  ///

  /// Return the current remote directory path.

  ///

  /// The current remote directory path.

  public string getRemotePath()
  {
    return remotePath;
  }
  ///

  /// Set the user name to use for logging into the remote server.

  ///

  /// Username

  public void setRemoteUser(string remoteUser)
  {
    this.remoteUser = remoteUser;
  }
  ///

  /// Set the password to user for logging into the remote server.

  ///

  /// Password

  public void setRemotePass(string remotePass)
  {
    this.remotePass = remotePass;
  }
  ///

  /// Return a string array containing the remote directory's file list.

  ///

  ///

  ///

  public string[] getFileList(string mask)
  {
    if (!logined)
    {
      login();
    }
    Socket cSocket = createDataSocket();
    sendCommand("NLST " + mask);
    if (!(retValue == 150 || retValue == 125))
    {
      throw new IOException(reply.Substring(4));
    }
    mes = "";
    while (true)
    {
      int bytes = cSocket.Receive(buffer, buffer.Length, 0);
      mes += ASCII.GetString(buffer, 0, bytes);
      if (bytes < buffer.Length)
      {
        break;
      }
    }
    char[] seperator = { '\n' };
    string[] mess = mes.Split(seperator);
    cSocket.Close();
    readReply();
    if (retValue != 226)
    {
      throw new IOException(reply.Substring(4));
    }
    return mess;
  }
  ///

  /// Return the size of a file.

  ///

  ///

  ///

  public long getFileSize(string fileName)
  {
    if (!logined)
    {
      login();
    }
    sendCommand("SIZE " + fileName);
    long size = 0;
    if (retValue == 213)
    {
      size = Int64.Parse(reply.Substring(4));
    }
    else
    {
      throw new IOException(reply.Substring(4));
    }
    return size;
  }
  ///

  /// Login to the remote server.

  ///

  public void login()
  {
    clientSocket = new
    Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
    IPEndPoint ep = new
    IPEndPoint(Dns.Resolve(remoteHost).AddressList[0], remotePort);
    try
    {
      clientSocket.Connect(ep);
    }
    catch (Exception)
    {
      throw new IOException("Couldn't connect to remote server");
    }
    readReply();
    if (retValue != 220)
    {
      close();
      throw new IOException(reply.Substring(4));
    }
    if (debug)
      Console.WriteLine("USER " + remoteUser);
    sendCommand("USER " + remoteUser);
    if (!(retValue == 331 || retValue == 230))
    {
      cleanup();
      throw new IOException(reply.Substring(4));
    }
    if (retValue != 230)
    {
      if (debug)
        Console.WriteLine("PASS xxx");
      sendCommand("PASS " + remotePass);
      if (!(retValue == 230 || retValue == 202))
      {
        cleanup();
        throw new IOException(reply.Substring(4));
      }
    }
    logined = true;
    Console.WriteLine("Connected to " + remoteHost);
    chdir(remotePath);
  }
  ///

  /// If the value of mode is true, set binary mode for downloads.

  /// Else, set Ascii mode.

  ///

  ///

  public void setBinaryMode(Boolean mode)
  {
    if (mode)
    {
      sendCommand("TYPE I");
    }
    else
    {
      sendCommand("TYPE A");
    }
    if (retValue != 200)
    {
      throw new IOException(reply.Substring(4));
    }
  }
  ///

  /// Download a file to the Assembly's local directory,

  /// keeping the same file name.

  ///

  ///

  public void download(string remFileName)
  {
    download(remFileName, "", false);
  }
  ///

  /// Download a remote file to the Assembly's local directory,

  /// keeping the same file name, and set the resume flag.

  ///

  ///

  ///

  public void download(string remFileName, Boolean resume)
  {
    download(remFileName, "", resume);
  }
  ///

  /// Download a remote file to a local file name which can include

  /// a path. The local file name will be created or overwritten,

  /// but the path must exist.

  ///

  ///

  ///

  public void download(string remFileName, string locFileName)
  {
    download(remFileName, locFileName, false);
  }
  ///

  /// Download a remote file to a local file name which can include

  /// a path, and set the resume flag. The local file name will be

  /// created or overwritten, but the path must exist.

  ///

  ///

  ///

  ///

  public void download(string remFileName, string
  locFileName, Boolean resume)
  {
    if (!logined)
    {
      login();
    }
    setBinaryMode(true);
    Console.WriteLine("Downloading file " + remFileName + " from " + remoteHost + "/" + remotePath);
    if (locFileName.Equals(""))
    {
      locFileName = remFileName;
    }
    if (!File.Exists(locFileName))
    {
      Stream st = File.Create(locFileName);
      st.Close();
    }
    FileStream output = new
    FileStream(locFileName, FileMode.Open);
    Socket cSocket = createDataSocket();
    long offset = 0;
    if (resume)
    {
      offset = output.Length;
      if (offset > 0)
      {
        sendCommand("REST " + offset);
        if (retValue != 350)
        {
          //throw new IOException(reply.Substring(4));

          //Some servers may not support resuming.

          offset = 0;
        }
      }
      if (offset > 0)
      {
        if (debug)
        {
          Console.WriteLine("seeking to " + offset);
        }
        long npos = output.Seek(offset, SeekOrigin.Begin);
        Console.WriteLine("new pos=" + npos);
      }
    }
    sendCommand("RETR " + remFileName);
    if (!(retValue == 150 || retValue == 125) )
    {
      throw new IOException(reply.Substring(4));
    }
    while (true)
    {
      bytes = cSocket.Receive(buffer, buffer.Length, 0);
      output.Write(buffer, 0, bytes);
      if (bytes <= 0)
      {
        break;
      }
    }
    output.Close();
    if (cSocket.Connected)
    {
      cSocket.Close();
    }
    Console.WriteLine("");
    readReply();
    if (!(retValue == 226 || retValue == 250))
    {
      throw new IOException(reply.Substring(4));
    }
  }
  ///

  /// Upload a file.

  ///

  ///

  public void upload(string fileName)
  {
    upload(fileName, false);
  }
  ///

  /// Upload a file and set the resume flag.

  ///

  ///

  ///

  public void upload(string fileName, Boolean resume)
  {
    if (!logined)
    {
      login();
    }
    Socket cSocket = createDataSocket();
    long offset = 0;
    if (resume)
    {
      try
      {
        setBinaryMode(true);
        offset = getFileSize(fileName);
      }
      catch (Exception)
      {
        offset = 0;
      }
    }
    if (offset > 0)
    {
      sendCommand("REST " + offset);
      if (retValue != 350)
      {
        //throw new IOException(reply.Substring(4));

        //Remote server may not support resuming.

        offset = 0;
      }
    }
    sendCommand("STOR " + Path.GetFileName(fileName));
    if (!(retValue == 125 || retValue == 150))
    {
      throw new IOException(reply.Substring(4));
    }
    // open input stream to read source file

    FileStream input = new
    FileStream(fileName, FileMode.Open);
    if (offset != 0)
    {
      if (debug)
      {
        Console.WriteLine("seeking to " + offset);
      }
      input.Seek(offset, SeekOrigin.Begin);
    }
    Console.WriteLine("Uploading file " + fileName + " to " + remotePath);
    while ((bytes = input.Read(buffer, 0, buffer.Length)) > 0)
    {
      cSocket.Send(buffer, bytes, 0);
    }
    input.Close();
    Console.WriteLine("");
    if (cSocket.Connected)
    {
      cSocket.Close();
    }
    readReply();
    if (!(retValue == 226 || retValue == 250))
    {
      throw new IOException(reply.Substring(4));
    }
  }
  ///

  /// Delete a file from the remote FTP server.

  ///

  ///

  public void deleteRemoteFile(string fileName)
  {
    if (!logined)
    {
      login();
    }
    sendCommand("DELE " + fileName);
    if (retValue != 250)
    {
      throw new IOException(reply.Substring(4));
    }
  }
  ///

  /// Rename a file on the remote FTP server.

  ///

  ///

  ///

  public void renameRemoteFile(string oldFileName, string
  newFileName)
  {
    if (!logined)
    {
      login();
    }
    sendCommand("RNFR " + oldFileName);
    if (retValue != 350)
    {
      throw new IOException(reply.Substring(4));
    }
    // known problem

    // rnto will not take care of existing file.

    // i.e. It will overwrite if newFileName exist

    sendCommand("RNTO " + newFileName);
    if (retValue != 250)
    {
      throw new IOException(reply.Substring(4));
    }
  }
  ///

  /// Create a directory on the remote FTP server.

  ///

  ///

  public void mkdir(string dirName)
  {
    if (!logined)
    {
      login();
    }
    sendCommand("MKD " + dirName);
    if (retValue != 257)
    {
      throw new IOException(reply.Substring(4));
    }
  }
  ///

  /// Delete a directory on the remote FTP server.

  ///

  ///

  public void rmdir(string dirName)
  {
    if (!logined)
    {
      login();
    }
    sendCommand("RMD " + dirName);
    if (retValue != 250)
    {
      throw new IOException(reply.Substring(4));
    }
  }
  ///

  /// Change the current working directory on the remote FTP server.

  ///

  ///

  public void chdir(string dirName)
  {
    if (dirName.Equals("."))
    {
      return;
    }
    if (!logined)
    {
      login();
    }
    sendCommand("CWD " + dirName);
    if (retValue != 250)
    {
      throw new IOException(reply.Substring(4));
    }
    this.remotePath = dirName;
    Console.WriteLine("Current directory is " + remotePath);
  }
  ///

  /// Close the FTP connection.

  ///

  public void close()
  {
    if (clientSocket != null)
    {
      sendCommand("QUIT");
    }
    cleanup();
    Console.WriteLine("Closing...");
  }
  ///

  /// Set debug mode.

  ///

  ///

  public void setDebug(Boolean debug)
  {
    this.debug = debug;
  }
  private void readReply()
  {
    mes = "";
    reply = readLine();
    retValue = Int32.Parse(reply.Substring(0, 3));
  }
  private void cleanup()
  {
    if (clientSocket != null)
    {
      clientSocket.Close();
      clientSocket = null;
    }
    logined = false;
  }
  private string readLine()
  {
    while (true)
    {
      bytes = clientSocket.Receive(buffer, buffer.Length, 0);
      mes += ASCII.GetString(buffer, 0, bytes);
      if (bytes < buffer.Length)
      {
        break;
      }
    }
    char[] seperator = { '\n' };
    string[] mess = mes.Split(seperator);
    if (mes.Length > 2)
    {
      mes = mess[mess.Length - 2];
    }
    else
    {
      mes = mess[0];
    }
    if (!mes.Substring(3, 1).Equals(" "))
    {
      return readLine();
    }
    if (debug)
    {
      for (int k = 0; k < mess.Length - 1; k++)
      {
        Console.WriteLine(mess[k]);
      }
    }
    return mes;
  }
  private void sendCommand(String command)
  {
    Byte[] cmdBytes =
      //Encoding.ASCII.GetBytes((command + "\r\n").ToCharArray());

    Encoding.Default.GetBytes((command + "\r\n").ToCharArray()); 
    clientSocket.Send(cmdBytes, cmdBytes.Length, 0);
    readReply();
  }
  private Socket createDataSocket()
  {
    sendCommand("PASV");
    if (retValue != 227)
    {
      throw new IOException(reply.Substring(4));
    }
    int index1 = reply.IndexOf('(');
    int index2 = reply.IndexOf(')');
    string ipData =
    reply.Substring(index1 + 1, index2 - index1 - 1);
    int[] parts = new int[6];
    int len = ipData.Length;
    int partCount = 0;
    string buf = "";
    for (int i = 0; i < len && partCount <= 6; i++)
    {
      char ch = Char.Parse(ipData.Substring(i, 1));
      if (Char.IsDigit(ch))
        buf += ch;
      else if (ch != ',')
      {
        throw new IOException("Malformed PASV reply: " +
        reply);
      }
      if (ch == ',' || i + 1 == len)
      {
        try
        {
          parts[partCount++] = Int32.Parse(buf);
          buf = "";
        }
        catch (Exception)
        {
          throw new IOException("Malformed PASV reply: " +
          reply);
        }
      }
    }
    string ipAddress = parts[0] + "." + parts[1] + "." +
    parts[2] + "." + parts[3];
    int port = (parts[4] << 8) + parts[5];
    Socket s = new
    Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
    IPEndPoint ep = new
    IPEndPoint(Dns.Resolve(ipAddress).AddressList[0], port);
    try
    {
      s.Connect(ep);
    }
    catch (Exception)
    {
      throw new IOException("Can't connect to remote server");
    }
    return s;
  }
}
}

以上所述就是本文的全部内容了，希望大家能够喜欢。