FTP文件传输

采用FTP PASV模式设计一个FTP服务器程序和一个FTP客户机程序，具有文件夹内容浏览和文件下载功能，服务器程序能够接收多个客户机的FTP请求并且能够对客户机身份进行验证。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

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

using System.Collections;
using System.Net.NetworkInformation;


namespace client
{
   

    public partial class Form1 : Form
    {
        TcpClient controltc;
        NetworkStream controlns;
        StreamReader controlsr;
        StreamWriter controlsw;



        private static string ext =null;


        public Form1（）
        {
            InitializeComponent（）;
            this.buttonUpDir.Enabled= false;

            Control.CheckForIllegalCross

 属性            大小     日期    时间   名称
----------- ---------  ---------- -----  ----
     目录           0  2018-11-27 10:17  client\
     目录           0  2018-11-13 12:46  client\.vs\
     目录           0  2018-11-13 12:46  client\.vs\client\
     目录           0  2018-11-13 12:46  client\.vs\client\v14\
     文件       44544  2018-01-07 03:33  client\.vs\client\v14\.suo
     文件       17408  2017-12-10 23:06  client\client.exe
     文件         985  2017-12-04 22:30  client\client.sln
     目录           0  2018-11-13 12:46  client\client\
     文件         189  2017-12-04 22:30  client\client\App.config
     目录           0  2018-11-13 12:46  client\client\bin\
     目录           0  2018-11-13 12:46  client\client\bin\Debug\
     文件       17408  2017-12-10 23:06  client\client\bin\Debug\client.exe
     文件         189  2017-12-04 22:30  client\client\bin\Debug\client.exe.config
     文件       34304  2017-12-10 23:06  client\client\bin\Debug\client.pdb
     文件       22696  2018-01-07 03:28  client\client\bin\Debug\client.vshost.exe
     文件         189  2017-12-04 22:30  client\client\bin\Debug\client.vshost.exe.config
     文件         490  2017-03-19 05:00  client\client\bin\Debug\client.vshost.exe.manifest
     文件        3950  2017-12-05 00:06  client\client\client.csproj
     文件       10672  2017-12-05 11:26  client\client\Form1.cs
     文件        8813  2017-12-05 01:12  client\client\Form1.Designer.cs
     文件        5817  2017-12-05 01:12  client\client\Form1.resx
     目录           0  2018-11-13 12:46  client\client\obj\
     目录           0  2018-11-13 12:46  client\client\obj\Debug\
     文件        1551  2018-01-07 03:28  client\client\obj\Debug\client.csproj.FileListAbsolute.txt
     文件        1012  2017-12-05 01:13  client\client\obj\Debug\client.csproj.GenerateResource.Cache
     文件        2384  2017-12-05 00:06  client\client\obj\Debug\client.csprojResolveAssemblyReference.cache
     文件       17408  2017-12-10 23:06  client\client\obj\Debug\client.exe
     文件         180  2017-12-05 01:13  client\client\obj\Debug\client.Form1.resources
     文件       34304  2017-12-10 23:06  client\client\obj\Debug\client.pdb
     文件         180  2017-12-05 00:06  client\client\obj\Debug\client.Properties.Resources.resources
     文件        1464  2017-12-05 08:54  client\client\obj\Debug\DesignTimeResolveAssemblyReferences.cache
............此处省略48个文件信息