[转载]C# FTP操作工具类

本文转载自《C# Ftp操作工具类》，仅对原文格式进行了整理。

介绍了几种FTP操作的函数，供后期编程时查阅。

参考一：

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Net;
 
using System.Globalization;
 
namespace FtpTest1
{
 
    public class FtpWeb
    {
        string ftpServerIP;
        string ftpRemotePath;
        string ftpUserID;
        string ftpPassword;
        string ftpURI;
 
        /// <summary>
        /// 连接FTP
        /// </summary>
        /// <param name="FtpServerIP">FTP连接地址</param>
        /// <param name="FtpRemotePath">指定FTP连接成功后的当前目录, 如果不指定即默认为根目录</param>
        /// <param name="FtpUserID">用户名</param>
        /// <param name="FtpPassword">密码</param>
        public FtpWeb(string FtpServerIP, string FtpRemotePath, string FtpUserID, string FtpPassword)
        {
            ftpServerIP = FtpServerIP;
            ftpRemotePath = FtpRemotePath;
            ftpUserID = FtpUserID;
            ftpPassword = FtpPassword;
            ftpURI = "ftp://" + ftpServerIP + "/" ;
        }
 
 
        static void Main() {
            //string file = "c:\aq3.gifa";
            //FileInfo fileInf = new FileInfo(file);
            //if (!fileInf.Exists)
            //{
            //    Console.WriteLine(file + " no exists");
            //}
            //else {
            //    Console.WriteLine("yes");
            //}
            //Console.ReadLine();
            FtpWeb fw = new FtpWeb("121.11.65.10", "", "aa1", "aa");
            string[] filePaths = { "c:\aq3.gif1", "c:\aq2.gif1", "c:\bsmain_runtime.log" };
            Console.WriteLine(fw.UploadFile(filePaths));
            Console.ReadLine();
        }
 
        //上传文件
        public string UploadFile( string[] filePaths ) {
            StringBuilder sb = new StringBuilder();
            if ( filePaths != null && filePaths.Length > 0 ){
                foreach( var file in filePaths ){
                    sb.Append(Upload( file ));
 
                }
            }
            return sb.ToString();
        }
 
         /// <summary>
        /// 上传文件
        /// </summary>
        /// <param name="filename"></param>
        private string Upload(string filename)
        {
            FileInfo fileInf = new FileInfo(filename);
            if ( !fileInf.Exists ){
                return filename + " 不存在!
";
            }
 
            string uri = ftpURI + fileInf.Name;
            FtpWebRequest reqFTP;
            reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(uri));
 
            reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);
            reqFTP.KeepAlive = false;
            reqFTP.Method = WebRequestMethods.Ftp.UploadFile;
            reqFTP.UseBinary = true;
            reqFTP.UsePassive = false;  //选择主动还是被动模式
            //Entering Passive Mode
            reqFTP.ContentLength = fileInf.Length;
            int buffLength = 2048;
            byte[] buff = new byte[buffLength];
            int contentLen;
            FileStream fs = fileInf.OpenRead();
            try
            {
                Stream strm = reqFTP.GetRequestStream();
                contentLen = fs.Read(buff, 0, buffLength);
                while (contentLen != 0)
                {
                    strm.Write(buff, 0, contentLen);
                    contentLen = fs.Read(buff, 0, buffLength);
                }
                strm.Close();
                fs.Close();
            }
            catch (Exception ex)
            {
                return "同步 "+filename+"时连接不上服务器!
";
                //Insert_Standard_ErrorLog.Insert("FtpWeb", "Upload Error --> " + ex.Message);
            }
            return "";
        }
 
 
        /// <summary>
        /// 下载
        /// </summary>
        /// <param name="filePath"></param>
        /// <param name="fileName"></param>
        public void Download(string filePath, string fileName)
        {
            FtpWebRequest reqFTP;
            try
            {
                FileStream outputStream = new FileStream(filePath + "\" + fileName, FileMode.Create);
 
                reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(ftpURI + fileName));
                reqFTP.Method = WebRequestMethods.Ftp.DownloadFile;
                reqFTP.UseBinary = true;
                reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);
                FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();
                Stream ftpStream = response.GetResponseStream();
                long cl = response.ContentLength;
                int bufferSize = 2048;
                int readCount;
                byte[] buffer = new byte[bufferSize];
 
                readCount = ftpStream.Read(buffer, 0, bufferSize);
                while (readCount > 0)
                {
                    outputStream.Write(buffer, 0, readCount);
                    readCount = ftpStream.Read(buffer, 0, bufferSize);
                }
 
                ftpStream.Close();
                outputStream.Close();
                response.Close();
            }
            catch (Exception ex)
            {
                Insert_Standard_ErrorLog.Insert("FtpWeb", "Download Error --> " + ex.Message);
            }
        }
 
        /// <summary>
        /// 删除文件
        /// </summary>
        /// <param name="fileName"></param>
        public void Delete(string fileName)
        {
            try
            {
                string uri = ftpURI + fileName;
                FtpWebRequest reqFTP;
                reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(uri));
 
                reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);
                reqFTP.KeepAlive = false;
                reqFTP.Method = WebRequestMethods.Ftp.DeleteFile;
 
                string result = String.Empty;
                FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();
                long size = response.ContentLength;
                Stream datastream = response.GetResponseStream();
                StreamReader sr = new StreamReader(datastream);
                result = sr.ReadToEnd();
                sr.Close();
                datastream.Close();
                response.Close();
            }
            catch (Exception ex)
            {
                Insert_Standard_ErrorLog.Insert("FtpWeb", "Delete Error --> " + ex.Message + "  文件名:" + fileName);
            }
        }
 
        /// <summary>
        /// 获取当前目录下明细(包含文件和文件夹)
        /// </summary>
        /// <returns></returns>
        public string[] GetFilesDetailList()
        {
            string[] downloadFiles;
            try
            {
                StringBuilder result = new StringBuilder();
                FtpWebRequest ftp;
                ftp = (FtpWebRequest)FtpWebRequest.Create(new Uri(ftpURI));
                ftp.Credentials = new NetworkCredential(ftpUserID, ftpPassword);
                ftp.Method = WebRequestMethods.Ftp.ListDirectoryDetails;
                WebResponse response = ftp.GetResponse();
                StreamReader reader = new StreamReader(response.GetResponseStream());
                string line = reader.ReadLine();
                line = reader.ReadLine();
                line = reader.ReadLine();
                while (line != null)
                {
                    result.Append(line);
                    result.Append("
");
                    line = reader.ReadLine();
                }
                result.Remove(result.ToString().LastIndexOf("
"), 1);
                reader.Close();
                response.Close();
                return result.ToString().Split('
');
            }
            catch (Exception ex)
            {
                downloadFiles = null;
                Insert_Standard_ErrorLog.Insert("FtpWeb", "GetFilesDetailList Error --> " + ex.Message);
                return downloadFiles;
            }
        }
 
        /// <summary>
        /// 获取当前目录下文件列表(仅文件)
        /// </summary>
        /// <returns></returns>
        public string[] GetFileList(string mask)
        {
            string[] downloadFiles;
            StringBuilder result = new StringBuilder();
            FtpWebRequest reqFTP;
            try
            {
                reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(ftpURI));
                reqFTP.UseBinary = true;
                reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);
                reqFTP.Method = WebRequestMethods.Ftp.ListDirectory;
                WebResponse response = reqFTP.GetResponse();
                StreamReader reader = new StreamReader(response.GetResponseStream());
 
                string line = reader.ReadLine();
                while (line != null)
                {
                    if (mask.Trim() != string.Empty && mask.Trim() != "*.*")
                    {
                        string mask_ = mask.Substring(0, mask.IndexOf("*"));
                        if (line.Substring(0, mask_.Length) == mask_)
                        {
                            result.Append(line);
                            result.Append("
");
                        }
                    }
                    else
                    {
                        result.Append(line);
                        result.Append("
");
                    }
                    line = reader.ReadLine();
                }
                result.Remove(result.ToString().LastIndexOf('
'), 1);
                reader.Close();
                response.Close();
                return result.ToString().Split('
');
            }
            catch (Exception ex)
            {
                downloadFiles = null;
                if (ex.Message.Trim() != "远程服务器返回错误: (550) 文件不可用(例如，未找到文件，无法访问文件)。")
                {
                    Insert_Standard_ErrorLog.Insert("FtpWeb", "GetFileList Error --> " + ex.Message.ToString());
                }
                return downloadFiles;
            }
        }
 
        /// <summary>
        /// 获取当前目录下所有的文件夹列表(仅文件夹)
        /// </summary>
        /// <returns></returns>
        public string[] GetDirectoryList()
        {
            string[] drectory = GetFilesDetailList();
            string m = string.Empty;
            foreach (string str in drectory)
            {
                if (str.Trim().Substring(0, 1).ToUpper() == "D")
                {
                    m += str.Substring(54).Trim() + "
";
                }
            }
 
            char[] n = new char[] { '
' };
            return m.Split(n);
        }
 
        /// <summary>
        /// 判断当前目录下指定的子目录是否存在
        /// </summary>
        /// <param name="RemoteDirectoryName">指定的目录名</param>
        public bool DirectoryExist(string RemoteDirectoryName)
        {
            string[] dirList = GetDirectoryList();
            foreach (string str in dirList)
            {
                if (str.Trim() == RemoteDirectoryName.Trim())
                {
                    return true;
                }
            }
            return false;
        }
 
        /// <summary>
        /// 判断当前目录下指定的文件是否存在
        /// </summary>
        /// <param name="RemoteFileName">远程文件名</param>
        public bool FileExist(string RemoteFileName)
        {
            string[] fileList = GetFileList("*.*");
            foreach (string str in fileList)
            {
                if (str.Trim() == RemoteFileName.Trim())
                {
                    return true;
                }
            }
            return false;
        }
 
        /// <summary>
        /// 创建文件夹
        /// </summary>
        /// <param name="dirName"></param>
        public void MakeDir(string dirName)
        {
            FtpWebRequest reqFTP;
            try
            {
                // dirName = name of the directory to create.
                reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(ftpURI + dirName));
                reqFTP.Method = WebRequestMethods.Ftp.MakeDirectory;
                reqFTP.UseBinary = true;
                reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);
                FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();
                Stream ftpStream = response.GetResponseStream();
 
                ftpStream.Close();
                response.Close();
            }
            catch (Exception ex)
            {
                Insert_Standard_ErrorLog.Insert("FtpWeb", "MakeDir Error --> " + ex.Message);
            }
        }
 
        /// <summary>
        /// 获取指定文件大小
        /// </summary>
        /// <param name="filename"></param>
        /// <returns></returns>
        public long GetFileSize(string filename)
        {
            FtpWebRequest reqFTP;
            long fileSize = 0;
            try
            {
                reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(ftpURI + filename));
                reqFTP.Method = WebRequestMethods.Ftp.GetFileSize;
                reqFTP.UseBinary = true;
                reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);
                FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();
                Stream ftpStream = response.GetResponseStream();
                fileSize = response.ContentLength;
 
                ftpStream.Close();
                response.Close();
            }
            catch (Exception ex)
            {
                Insert_Standard_ErrorLog.Insert("FtpWeb", "GetFileSize Error --> " + ex.Message);
            }
            return fileSize;
        }
 
        /// <summary>
        /// 改名
        /// </summary>
        /// <param name="currentFilename"></param>
        /// <param name="newFilename"></param>
        public void ReName(string currentFilename, string newFilename)
        {
            FtpWebRequest reqFTP;
            try
            {
                reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(ftpURI + currentFilename));
                reqFTP.Method = WebRequestMethods.Ftp.Rename;
                reqFTP.RenameTo = newFilename;
                reqFTP.UseBinary = true;
                reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);
                FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();
                Stream ftpStream = response.GetResponseStream();
 
                ftpStream.Close();
                response.Close();
            }
            catch (Exception ex)
            {
                Insert_Standard_ErrorLog.Insert("FtpWeb", "ReName Error --> " + ex.Message);
            }
        }
 
        /// <summary>
        /// 移动文件
        /// </summary>
        /// <param name="currentFilename"></param>
        /// <param name="newFilename"></param>
        public void MovieFile(string currentFilename, string newDirectory)
        {
            ReName(currentFilename, newDirectory);
        }

<--------------------------分割线------------------------->

参考二：

using System.IO;
using System.Net;
using System.Text;
using System.Diagnostics;
using System.Text.RegularExpressions;

    //从ftp上下载文件
    private void Download(string filePath, string ImageSrc, string ImageName, string ftpServerIP, string 
 

ftpUserName, string ftpPwd)
    {
        if (!Directory.Exists(filePath))
        {
            Directory.CreateDirectory(filePath);
        }
        using (FileStream OutputStream = new FileStream(filePath + "\" + ImageName, FileMode.Create))
        {
            FtpWebRequest ReqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + ftpServerIP + "/" + 

ImageSrc));

            ReqFTP.Method = WebRequestMethods.Ftp.DownloadFile;

            ReqFTP.UseBinary = true;

            ReqFTP.Credentials = new NetworkCredential(ftpUserName, ftpPwd);

            using (FtpWebResponse response = (FtpWebResponse)ReqFTP.GetResponse())
            {

                using (Stream FtpStream = response.GetResponseStream())
                {

                    long Cl = response.ContentLength;

                    int bufferSize = 2048;

                    int readCount;

                    byte[] buffer = new byte[bufferSize];

                    readCount = FtpStream.Read(buffer, 0, bufferSize);

                    while (readCount > 0)
                    {
                        OutputStream.Write(buffer, 0, readCount);

                        readCount = FtpStream.Read(buffer, 0, bufferSize);
                    }

                    FtpStream.Close();
                }

                response.Close();

            }

            OutputStream.Close();
        }

    }
        //从服务器上传文件到FTP上
    private void UploadSmall(string sFileDstPath, string FolderName, string ftpServerIP, string ftpUserName, 

string ftpPwd)
    {

        FileInfo fileInf = new FileInfo(sFileDstPath);

        FtpWebRequest reqFTP;

        reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + ftpServerIP + "/" + FolderName + "/" + 

fileInf.Name));

        reqFTP.Credentials = new NetworkCredential(ftpUserName, ftpPwd);

        reqFTP.KeepAlive = false;

        reqFTP.Method = WebRequestMethods.Ftp.UploadFile;

        reqFTP.UseBinary = true;

        reqFTP.ContentLength = fileInf.Length;

        int buffLength = 2048;

        byte[] buff = new byte[buffLength];

        int contentLen;

        using (FileStream fs = fileInf.OpenRead())
        {

            using (Stream strm = reqFTP.GetRequestStream())
            {

                contentLen = fs.Read(buff, 0, buffLength);

                while (contentLen != 0)
                {

                    strm.Write(buff, 0, contentLen);

                    contentLen = fs.Read(buff, 0, buffLength);
                }

                strm.Close();
            }

            fs.Close();
        }

    }
    //删除服务器上的文件
    private void DeleteWebServerFile(string sFilePath)
    {
        if (File.Exists(sFilePath))
        {
            File.Delete(sFilePath);
        }
    }
    //删除FTP上的文件
    private void DeleteFtpFile(string[] IName, string FolderName, string ftpServerIP, string ftpUserName, string 

ftpPwd)
    {
        foreach (string ImageName in IName)
        {
            string[] FileList = GetFileList(FolderName, ftpServerIP, ftpUserName, ftpPwd);
            for (int i = 0; i < FileList.Length; i++)
            {
                string Name = FileList[i].ToString();
                if (Name == ImageName)
                {
                    FtpWebRequest ReqFTP;

                    ReqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + ftpServerIP + "/" + 

FolderName + "/" + ImageName));

                    ReqFTP.Credentials = new NetworkCredential(ftpUserName, ftpPwd);

                    ReqFTP.KeepAlive = false;

                    ReqFTP.Method = WebRequestMethods.Ftp.DeleteFile;

                    ReqFTP.UseBinary = true;

                    using (FtpWebResponse Response = (FtpWebResponse)ReqFTP.GetResponse())
                    {

                        long size = Response.ContentLength;

                        using (Stream datastream = Response.GetResponseStream())
                        {

                            using (StreamReader sr = new StreamReader(datastream))
                            {

                                sr.ReadToEnd();

                                sr.Close();
                            }

                            datastream.Close();
                        }

                        Response.Close();
                    }
                }
            }

        }

    }
    //检查文件是否存在
    public string[] GetFileList(string FolderName, string ftpServerIP, string ftpUserName, string ftpPwd)
    {
        string[] downloadFiles;

        StringBuilder result = new StringBuilder();

        FtpWebRequest reqFTP;
        try
        {
            reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + ftpServerIP + "/" + FolderName + 

"/"));

            reqFTP.UseBinary = true;

            reqFTP.Credentials = new NetworkCredential(ftpUserName, ftpPwd);

            reqFTP.Method = WebRequestMethods.Ftp.ListDirectory;

            WebResponse response = reqFTP.GetResponse();

            StreamReader reader = new StreamReader(response.GetResponseStream());

            string line = reader.ReadLine();

            while (line != null)
            {
                result.Append(line);

                result.Append("
");

                line = reader.ReadLine();
            }
            // to remove the trailing '
'        
            result.Remove(result.ToString().LastIndexOf('
'), 1);

            reader.Close();

            response.Close();

            return result.ToString().Split('
');
        }
        catch (Exception ex)
        {
            downloadFiles = null;
            return downloadFiles;
        }
    }
    //从客户端上传文件到FTP上
    private void UploadFtp(HttpPostedFile sFilePath, string filename, string FolderName, string ftpServerIP, 

string ftpUserName, string ftpPwd)
    {
        //获取的服务器路径
        //FileInfo fileInf = new FileInfo(sFilePath);

        FtpWebRequest reqFTP;

        reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + ftpServerIP + "/" + FolderName + "/" + 

filename));

        reqFTP.Credentials = new NetworkCredential(ftpUserName, ftpPwd);

        reqFTP.KeepAlive = false;

        reqFTP.Method = WebRequestMethods.Ftp.UploadFile;

        reqFTP.UseBinary = true;

        reqFTP.ContentLength = sFilePath.ContentLength;
        //设置缓存
        int buffLength = 2048;

        byte[] buff = new byte[buffLength];

        int contentLen;

        using (Stream fs = sFilePath.InputStream)
        {

            using (Stream strm = reqFTP.GetRequestStream())
            {

                contentLen = fs.Read(buff, 0, buffLength);

                while (contentLen != 0)
                {

                    strm.Write(buff, 0, contentLen);

                    contentLen = fs.Read(buff, 0, buffLength);
                }

                strm.Close();
            }

            fs.Close();
        }

    }
    //创建目录
    private void CreateDirectory(string FolderName, string ftpServerIP, string ftpUserName, string ftpPwd)
    {
        //创建日期目录
        try
        {
            FtpWebRequest reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + ftpServerIP + "/" + 

FolderName));

            reqFTP.UseBinary = true;

            reqFTP.Credentials = new NetworkCredential(ftpUserName, ftpPwd);

            reqFTP.KeepAlive = false;

            reqFTP.Method = WebRequestMethods.Ftp.MakeDirectory;

            FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();
        }
        catch
        {
            ClientScript.RegisterStartupScript(this.GetType(), "", "<script>alert('系统忙，请稍后再

试！');location.href=location.href;</script>");
        }
    }
    //检查日期目录和文件是否存在
    private static Regex regexName = new Regex(@"[^s]*$", RegexOptions.Compiled);
    private bool CheckFileOrPath(string FolderName, string ftpServerIP, string ftpUserName, string ftpPwd)
    {
        //检查一下日期目录是否存在
        FtpWebRequest reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + ftpServerIP + "/"));

        reqFTP.UseBinary = true;

        reqFTP.Credentials = new NetworkCredential(ftpUserName, ftpPwd);

        reqFTP.Method = WebRequestMethods.Ftp.ListDirectoryDetails;

        Stream stream = reqFTP.GetResponse().GetResponseStream();

        using (StreamReader sr = new StreamReader(stream))
        {
            string line = sr.ReadLine();

            while (!string.IsNullOrEmpty(line))
            {
                GroupCollection gc = regexName.Match(line).Groups;
                if (gc.Count != 1)
                {
                    throw new ApplicationException("FTP 返回的字串格式不正确");
                }

                string path = gc[0].Value;
                if (path == FolderName)
                {
                    return true;
                }

                line = sr.ReadLine();
            }
        }

        return false;

    }
}

<--------------------------分割线------------------------->

参考三：

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

/// <summary>
/// FTPClient 的摘要说明。
/// </summary>
public class FTPClient
{
    #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>
    /// <param name="remoteHost"></param>
    /// <param name="remotePath"></param>
    /// <param name="remoteUser"></param>
    /// <param name="remotePass"></param>
    /// <param name="remotePort"></param>
    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 登陆
    /// <summary>
    /// FTP服务器IP地址
    /// </summary>
    private string strRemoteHost;
    public string RemoteHost
    {
        get
        {
            return strRemoteHost;
        }
        set
        {
            strRemoteHost = value;
        }
    }
    /// <summary>
    /// FTP服务器端口
    /// </summary>
    private int strRemotePort;
    public int RemotePort
    {
        get
        {
            return strRemotePort;
        }
        set
        {
            strRemotePort = value;
        }
    }
    /// <summary>
    /// 当前服务器目录
    /// </summary>
    private string strRemotePath;
    public string RemotePath
    {
        get
        {
            return strRemotePath;
        }
        set
        {
            strRemotePath = value;
        }
    }
    /// <summary>
    /// 登录用户账号
    /// </summary>
    private string strRemoteUser;
    public string RemoteUser
    {
        set
        {
            strRemoteUser = value;
        }
    }
    /// <summary>
    /// 用户登录密码
    /// </summary>
    private string strRemotePass;
    public string RemotePass
    {
        set
        {
            strRemotePass = value;
        }
    } /// <summary>
    /// 是否登录
    /// </summary>
    private Boolean bConnected;
    public bool Connected
    {
        get
        {
            return bConnected;
        }
    }
    #endregion
    #region 链接
    /// <summary>
    /// 建立连接 
    /// </summary>
    public void Connect()
    {
        socketControl = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        IPEndPoint ep = new IPEndPoint(IPAddress.Parse(RemoteHost), strRemotePort);
        // 链接
        try
        {
            socketControl.Connect(ep);
        }
        catch (Exception)
        {
            throw new IOException("Couldn't connect to remote server");
        }   // 获取应答码
        ReadReply();
        if (iReplyCode != 220)
        {
            DisConnect();
            throw new IOException(strReply.Substring(4));
        }   // 登陆
        SendCommand("USER " + strRemoteUser);
        if (!(iReplyCode == 331 || iReplyCode == 230))
        {
            CloseSocketConnect();//关闭连接
            throw new IOException(strReply.Substring(4));
        }
        if (iReplyCode != 230)
        {
            SendCommand("PASS " + strRemotePass);
            if (!(iReplyCode == 230 || iReplyCode == 202))
            {
                CloseSocketConnect();//关闭连接
                throw new IOException(strReply.Substring(4));
            }
        }
        bConnected = true;   // 切换到目录
        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>
    /// <returns></returns>
    public string[] Dir(string strMask)
    {
        // 建立链接
        if (!bConnected)
        {
            Connect();
        }   //建立进行数据连接的socket
        Socket socketData = CreateDataSocket();

        //传送命令
        SendCommand("NLST " + strMask);   //分析应答代码
        if (!(iReplyCode == 150 || iReplyCode == 125 || iReplyCode == 226))
        {
            throw new IOException(strReply.Substring(4));
        }   //获得结果
        strMsg = "";
        while (true)
        {
            int iBytes = socketData.Receive(buffer, buffer.Length, 0);
            strMsg += ASCII.GetString(buffer, 0, iBytes);
            if (iBytes < buffer.Length)
            {
                break;
            }
        }
        char[] seperator = { '
' };
        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;
    }
    /// <summary>
    /// 获取文件大小
    /// </summary>
    /// <param name="strFileName">文件名</param>
    /// <returns>文件大小</returns>
    private 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>
    /// 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)
    {
        if (!bConnected)
        {
            Connect();
        }
        SetTransferType(TransferType.Binary);
        if (strLocalFileName.Equals(""))
        {
            strLocalFileName = strRemoteFileName;
        }
        if (!File.Exists(strLocalFileName))
        {
            Stream st = File.Create(strLocalFileName);
            st.Close();
        }
        FileStream output = new
         FileStream(strFolder + "\" + strLocalFileName, FileMode.Create);
        Socket socketData = CreateDataSocket();
        SendCommand("RETR " + strRemoteFileName);
        if (!(iReplyCode == 150 || iReplyCode == 125
         || iReplyCode == 226 || iReplyCode == 250))
        {
            throw new IOException(strReply.Substring(4));
        }
        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)
        {
            //strFile是完整的文件名(包含路径)
            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();
        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));
            }
        }
    }

    #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 内部变量
    /// <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;
    Byte[] buffer = new Byte[BLOCK_SIZE];
    /// <summary>
    /// 编码方式
    /// </summary>
    Encoding ASCII = Encoding.ASCII;
    #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("Can't connect to remote server");
        }
        return s;
    }
    /// <summary>
    /// 关闭socket连接(用于登录以前)
    /// </summary>
    private void CloseSocketConnect()
    {
        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()
    {
        while (true)
        {
            int iBytes = socketControl.Receive(buffer, buffer.Length, 0);
            strMsg += ASCII.GetString(buffer, 0, iBytes);
            if (iBytes < buffer.Length)
            {
                break;
            }
        }
        char[] seperator = { '
' };
        string[] mess = strMsg.Split(seperator);
        if (strMsg.Length > 2)
        {
            strMsg = mess[mess.Length - 2];
            //seperator[0]是10,换行符是由13和0组成的,分隔后10后面虽没有字符串,
            //但也会分配为空字符串给后面(也是最后一个)字符串数组,
            //所以最后一个mess是没用的空字符串
            //但为什么不直接取mess[0],因为只有最后一行字符串应答码与信息之间有空格
        }
        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>
    private void SendCommand(String strCommand)
    {
        //Byte[] cmdBytes =
        // Encoding.ASCII.GetBytes((strCommand + "
").ToCharArray());
        byte[] cmdBytes = Encoding.GetEncoding("gb2312").GetBytes((strCommand + "
").ToCharArray());
        socketControl.Send(cmdBytes, cmdBytes.Length, 0);
        ReadReply();
    }
    #endregion
}

<--------------------------分割线------------------------->

参考四：

介绍
微软的.net framework 2.0相对于1.x来说增加了对FTP的支持。以前为了符合我的需求，我不等不使用第三方类库来实现FTP功能，但是为了可靠，还是使用.net framework的类比较好。我的这段代码没有做成可重复使用的类库的形式，但它却是比较容易理解的并能满足你的需求。它可以实现上传，下载，删除等任意功能。在这篇文章的后面将给大家出示.net 2.0下实现ftp的简单代码，使用的语言是c#。或许是因为这是.net新增的类，又或许是第三方类库已经能很好的实现你的需求，.net 2.0的这部分类库并没有得到足够的关注。

背景
作为我的工作的一部分，我已经使用了ftp模块，但是我只能在.net 1.1中去使用它，所以我不能深入的研究.net 2.0下ftp的实现。但是我相信，.ne 2.0下对ftp的支持是非常好的。

代码
不要忘记引入命名空间

using System.Net;
using System.IO;

下面的几个步骤包括了使用FtpWebRequest类实现ftp功能的一般过程

1、创建一个FtpWebRequest对象，指向ftp服务器的uri
2、设置ftp的执行方法（上传，下载等）
3、给FtpWebRequest对象设置属性（是否支持ssl，是否使用二进制传输等）
4、设置登录验证（用户名，密码）
5、执行请求
6、接收相应流（如果需要的话）
7、如果没有打开的流，则关闭ftp请求

开发任何ftp应用程序都需要一个相关的ftp服务器及它的配置信息。FtpWebRequest暴露了一些属性来设置这些信息。
接下来的代码示例了上传功能
首先设置一个uri地址，包括路径和文件名。这个uri被使用在FtpWebRequest实例中。
然后根据ftp请求设置FtpWebRequest对象的属性
其中一些重要的属性如下：
    ·Credentials - 指定登录ftp服务器的用户名和密码。
    ·KeepAlive - 指定连接是应该关闭还是在请求完成之后关闭，默认为true
    ·UseBinary - 指定文件传输的类型。有两种文件传输模式，一种是Binary，另一种是ASCII。两种方法在传输时，字节的第8位是不同的。ASCII使用第8位作为错误控制，而Binary的8位都是有意义的。所以当你使用ASCII传输时要小心一些。简单的说，如果能用记事本读和写的文件用ASCII传输就是安全的，而其他的则必须使用Binary模式。当然使用Binary模式发送ASCII文件也是非常好的。
    ·UsePassive - 指定使用主动模式还是被动模式。早先所有客户端都使用主动模式，而且工作的很好，而现在因为客户端防火墙的存在，将会关闭一些端口，这样主动模式将会失败。在这种情况下就要使用被动模式，但是一些端口也可能被服务器的防火墙封掉。不过因为ftp服务器需要它的ftp服务连接到一定数量的客户端，所以他们总是支持被动模式的。这就是我们为什么要使用被动模式的原意，为了确保数据可以正确的传输，使用被动模式要明显优于主动模式。（译者注：主动（PORT）模式建立数据传输通道是由服务器端发起的，服务器使用20端口连接客户端的某一个大于1024的端口；在被动（PASV）模式中，数据传输的通道的建立是由FTP客户端发起的，他使用一个大于1024的端口连接服务器的1024以上的某一个端口）
    ·ContentLength - 设置这个属性对于ftp服务器是有用的，但是客户端不使用它，因为FtpWebRequest忽略这个属性，所以在这种情况下，该属性是无效的。但是如果我们设置了这个属性，ftp服务器将会提前预知文件的大小（在upload时会有这种情况）
    ·Method - 指定当前请求是什么命令（upload，download，filelist等）。这个值定义在结构体WebRequestMethods.Ftp中。

private void Upload(string filename)
{
    FileInfo fileInf = new FileInfo(filename);
    string uri = "ftp://" + ftpServerIP + "/" + fileInf.Name;
    FtpWebRequest reqFTP; 

    // 根据uri创建FtpWebRequest对象 
    reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + ftpServerIP + "/" + fileInf.Name)); 

    // ftp用户名和密码
    reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword); 

    // 默认为true，连接不会被关闭
    // 在一个命令之后被执行
    reqFTP.KeepAlive = false; 

    // 指定执行什么命令
    reqFTP.Method = WebRequestMethods.Ftp.UploadFile; 

    // 指定数据传输类型
    reqFTP.UseBinary = true; 

    // 上传文件时通知服务器文件的大小
    reqFTP.ContentLength = fileInf.Length; 

    // 缓冲大小设置为2kb
    int buffLength = 2048;

    byte[] buff = new byte[buffLength];
    int contentLen; 

    // 打开一个文件流 (System.IO.FileStream) 去读上传的文件
    FileStream fs = fileInf.OpenRead(); 
    try
    {
        // 把上传的文件写入流
        Stream strm = reqFTP.GetRequestStream(); 

        // 每次读文件流的2kb
        contentLen = fs.Read(buff, 0, buffLength); 

        // 流内容没有结束
        while (contentLen != 0)
        {
            // 把内容从file stream 写入 upload stream
            strm.Write(buff, 0, contentLen);

            contentLen = fs.Read(buff, 0, buffLength);
        } 

        // 关闭两个流
        strm.Close();
        fs.Close();
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message, "Upload Error");
    }
}

以上代码简单的示例了ftp的上传功能。创建一个指向某ftp服务器的FtpWebRequest对象，然后设置其不同的属性Credentials，KeepAlive，Method，UseBinary，ContentLength。
打开本地机器上的文件，把其内容写入ftp请求流。缓冲的大小为2kb，无论上传大文件还是小文件，这都是一个合适的大小。

private void Download(string filePath, string fileName)
{
    FtpWebRequest reqFTP;

    try
    {
        FileStream outputStream = new FileStream(filePath + "\" + fileName, FileMode.Create); 

        reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + ftpServerIP + "/" + fileName));

        reqFTP.Method = WebRequestMethods.Ftp.DownloadFile;

        reqFTP.UseBinary = true;

        reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);

        FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();

        Stream ftpStream = response.GetResponseStream();

        long cl = response.ContentLength;

        int bufferSize = 2048;

        int readCount;

        byte[] buffer = new byte[bufferSize];

        readCount = ftpStream.Read(buffer, 0, bufferSize);

        while (readCount > 0)
        {
            outputStream.Write(buffer, 0, readCount);

            readCount = ftpStream.Read(buffer, 0, bufferSize);
        }

        ftpStream.Close();

        outputStream.Close();

        response.Close();
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
    }
}

上面的代码实现了从ftp服务器上下载文件的功能。这不同于之前所提到的上传功能，下载需要一个响应流，它包含着下载文件的内容。这个下载的文件是在FtpWebRequest对象中的uri指定的。在得到所请求的文件后，通过FtpWebRequest对象的GetResponse()方法下载文件。它将把文件作为一个流下载到你的客户端的机器上。

注意：我们可以设置文件在我们本地机器上的存放路径和名称。

public string[] GetFileList()
{    
    string[] downloadFiles;    
    StringBuilder result = new StringBuilder();    
    FtpWebRequest reqFTP;    
    try    
    {        
        reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + ftpServerIP + "/"));        
        reqFTP.UseBinary = true;        
        reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);        
        reqFTP.Method = WebRequestMethods.Ftp.ListDirectory;        
        WebResponse response = reqFTP.GetResponse();        
        StreamReader reader = new StreamReader(response.GetResponseStream());        
        string line = reader.ReadLine();        
        while (line != null)        
        {            
            result.Append(line);            
            result.Append("
");            
            line = reader.ReadLine();        
        }        
        // to remove the trailing '
'        
        result.Remove(result.ToString().LastIndexOf('
'), 1);        
        reader.Close();        
        response.Close();        
        return result.ToString().Split('
');    
    }    
    catch (Exception ex)    
    {        
        System.Windows.Forms.MessageBox.Show(ex.Message);        
        downloadFiles = null;        
        return downloadFiles;    
    }
}

上面的代码示例了如何从ftp服务器上获得文件列表。uri指向ftp服务器的地址。我们使用StreamReader对象来存储一个流，文件名称列表通过“ ”分隔开，也就是说每一个文件名称都占一行。你可以使用StreamReader对象的ReadToEnd()方法来得到文件列表。上面的代码中我们用一个StringBuilder对象来保存文件名称，然后把结果通过分隔符分开后作为一个数组返回。我确定只是一个比较好的方法。

其他的实现如Rename，Delete，GetFileSize，FileListDetails，MakeDir等与上面的几段代码类似，就不多说了。

注意：实现重命名的功能时，要把新的名字设置给FtpWebRequest对象的RenameTo属性。连接指定目录的时候，需要在FtpWebRequest对象所使用的uri中指明。


需要注意的地方
你在编码时需要注意以下几点：
    ·除非EnableSsl属性被设置成true，否作所有数据，包括你的用户名和密码都将明文发给服务器，任何监视网络的人都可以获取到你连接服务器的验证信息。如果你连接的ftp服务器提供了SSL，你就应当把EnableSsl属性设置为true。
    ·如果你没有访问ftp服务器的权限，将会抛出SecurityException错误
    ·发送请求到ftp服务器需要调用GetResponse方法。当请求的操作完成后，一个FtpWebResponse对象将返回。这个FtpWebResponse对象提供了操作的状态和已经从ftp服务器上下载的数据。FtpWebResponse对象的StatusCode属性提供了ftp服务器返回的最后的状态代码。FtpWebResponse对象的StatusDescription属性为这个状态代码的描述。