C# 实现FTP客户端

 using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Net;
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
 
 namespace FtpClient
 {
     public class FtpHelper
     {
         #region 属性与构造函数
 
         /// <summary>
         /// IP地址
         /// </summary>
         public string IpAddr { get; set; }
 
         /// <summary>
         /// 相对路径
         /// </summary>
         public string RelatePath { get; set; }
 
         /// <summary>
         /// 端口号
         /// </summary>
         public string Port { get; set; }
 
         /// <summary>
         /// 用户名
         /// </summary>
         public string UserName { get; set; }
 
         /// <summary>
         /// 密码
         /// </summary>
         public string Password { get; set; }
 
        
 
         public FtpHelper() {
 
         }
 
         public FtpHelper(string ipAddr, string port, string userName, string password) {
             this.IpAddr = ipAddr;
             this.Port = port;
             this.UserName = userName;
             this.Password = password;
         }
 
         #endregion
 
         #region 方法
 
 
         /// <summary>
         /// 下载文件
         /// </summary>
         /// <param name="filePath"></param>
         /// <param name="isOk"></param>
         public void DownLoad(string filePath, out bool isOk) {
             string method = WebRequestMethods.Ftp.DownloadFile;
             var statusCode = FtpStatusCode.DataAlreadyOpen;
             FtpWebResponse response = callFtp(method);
             ReadByBytes(filePath, response, statusCode, out isOk);
         }
 
         public void UpLoad(string file,out bool isOk)
         {
             isOk = false;
             FileInfo fi = new FileInfo(file);
             FileStream fs = fi.OpenRead();
             long length = fs.Length;
             string uri = string.Format("ftp://{0}:{1}{2}", this.IpAddr, this.Port, this.RelatePath);
             FtpWebRequest request = (FtpWebRequest)WebRequest.Create(uri);
             request.Credentials = new NetworkCredential(UserName, Password);
             request.Method = WebRequestMethods.Ftp.UploadFile;
             request.UseBinary = true;
             request.ContentLength = length;
             request.Timeout = 10 * 1000;
             try
             {
                 Stream stream = request.GetRequestStream();
 
                 int BufferLength = 2048; //2K   
                 byte[] b = new byte[BufferLength];
                 int i;
                 while ((i = fs.Read(b, 0, BufferLength)) > 0)
                 {
                     stream.Write(b, 0, i);
                 }
                 stream.Close();
                 stream.Dispose();
                 isOk = true;
             }
             catch (Exception ex)
             {
                 Console.WriteLine(ex.ToString());
             }
             finally {
                 if (request != null)
                 {
                     request.Abort();
                     request = null;
                 }
             }
         }
 
         /// <summary>
         /// 删除文件
         /// </summary>
         /// <param name="isOk"></param>
         /// <returns></returns>
         public string[] DeleteFile(out bool isOk) {
             string method = WebRequestMethods.Ftp.DeleteFile;
             var statusCode = FtpStatusCode.FileActionOK;
             FtpWebResponse response = callFtp(method);
             return ReadByLine(response, statusCode, out isOk);
         }
 
         /// <summary>
         /// 展示目录
         /// </summary>
         public string[] ListDirectory(out bool isOk)
         {
             string method = WebRequestMethods.Ftp.ListDirectoryDetails;
             var statusCode = FtpStatusCode.DataAlreadyOpen;
             FtpWebResponse response= callFtp(method);
             return ReadByLine(response, statusCode, out isOk);
         }
 
         /// <summary>
         /// 设置上级目录
         /// </summary>
         public void SetPrePath()
         {
             string relatePath = this.RelatePath;
             if (string.IsNullOrEmpty(relatePath) || relatePath.LastIndexOf("/") == 0 )
             {
                 relatePath = "";
             }
             else {
                 relatePath = relatePath.Substring(0, relatePath.LastIndexOf("/"));
             }
             this.RelatePath = relatePath;
         }
 
         #endregion
 
         #region 私有方法
 
         /// <summary>
         /// 调用Ftp,将命令发往Ftp并返回信息
         /// </summary>
         /// <param name="method">要发往Ftp的命令</param>
         /// <returns></returns>
         private FtpWebResponse callFtp(string method)
         {
             string uri = string.Format("ftp://{0}:{1}{2}", this.IpAddr, this.Port, this.RelatePath);
             FtpWebRequest request; request = (FtpWebRequest)FtpWebRequest.Create(uri);
             request.UseBinary = true;
             request.UsePassive = true;
             request.Credentials = new NetworkCredential(UserName, Password);
             request.KeepAlive = false;
             request.Method = method;
             FtpWebResponse response = (FtpWebResponse)request.GetResponse();
             return response;
         }
 
         /// <summary>
         /// 按行读取
         /// </summary>
         /// <param name="response"></param>
         /// <param name="statusCode"></param>
         /// <param name="isOk"></param>
         /// <returns></returns>
         private string[] ReadByLine(FtpWebResponse response, FtpStatusCode statusCode,out bool isOk) {
             List<string> lstAccpet = new List<string>();
             int i = 0;
             while (true)
             {
                 if (response.StatusCode == statusCode)
                 {
                     using (StreamReader sr = new StreamReader(response.GetResponseStream()))
                     {
                         string line = sr.ReadLine();
                         while (!string.IsNullOrEmpty(line))
                         {
                             lstAccpet.Add(line);
                             line = sr.ReadLine();
                         }
                     }
                     isOk = true;
                     break;
                 }
                 i++;
                 if (i > 10)
                 {
                     isOk = false;
                     break;
                 }
                 Thread.Sleep(200);
             }
             response.Close();
             return lstAccpet.ToArray();
         }
 
         private void ReadByBytes(string filePath,FtpWebResponse response, FtpStatusCode statusCode, out bool isOk)
         {
             isOk = false;
             int i = 0;
             while (true)
 
             {
                 if (response.StatusCode == statusCode)
                 {
                     long length = response.ContentLength;
                     int bufferSize = 2048;
                     int readCount;
                     byte[] buffer = new byte[bufferSize];
                     using (FileStream outputStream = new FileStream(filePath, FileMode.Create))
                     {
 
                         using (Stream ftpStream = response.GetResponseStream())
                         {
                             readCount = ftpStream.Read(buffer, 0, bufferSize);
                             while (readCount > 0)
                             {
                                 outputStream.Write(buffer, 0, readCount);
                                 readCount = ftpStream.Read(buffer, 0, bufferSize);
                             }
                         }
                     }
                     break;
                 }
                 i++;
                 if (i > 10)
                 {
                     isOk = false;
                     break;
                 }
                 Thread.Sleep(200);
             }
             response.Close();
         }
         #endregion
     }
 
     /// <summary>
     /// Ftp内容类型枚举
     /// </summary>
     public enum FtpContentType
     {
         undefined = 0,
         file = 1,
         folder = 2
     }
 }