C ＃ set up FTP server and realize file uploading and downloading

build ftp Server and realize file uploading and downloading

1、 Create a form

2、 Introduce namespace

windows System building FTP Server tutorial , Refer to the link below
Thanks to the author of this link ：https://blog.csdn.net/weixin_43908647/article/details/113140942;

3、 The specific code is as follows ：

 public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
		//windows System building FTP Server tutorial , Refer to the link below 
        // Thanks to the author of this link ：https://blog.csdn.net/weixin_43908647/article/details/113140942;  

        string FTPAddress = "ftp://***.***.***.***:21"; //ftp Server address 
        string FTPUsername = "******";   //ftp Server user name 
        string FTPPwd = "******";//ftp Server password 
        // Upload files 
        private void button1_Click(object sender, EventArgs e)
        {
            string LocalPath = "d:\\ftp\\a.txt"; // Files to be uploaded 
            FileInfo f = new FileInfo(LocalPath);
            string FileName = f.Name;
            string FTPPath = FTPAddress + "/" + FileName; //
            // Implement file transfer protocol  (FTP)  client 
            FtpWebRequest reqFtp = (FtpWebRequest)FtpWebRequest.Create(new Uri(FTPPath));
            reqFtp.UseBinary = true;
            reqFtp.Credentials = new NetworkCredential(FTPUsername, FTPPwd); // Set communication credentials , Input ftp Server user name and password 
            reqFtp.KeepAlive = false; // Close when the request is complete ftp Connect 
            reqFtp.Method = WebRequestMethods.Ftp.UploadFile;// Calling the upload method 
            reqFtp.ContentLength = f.Length;
            int buffLength = 2048;
            byte[] buff = new byte[buffLength];
            int contentLen;
            // Read and upload local file data 
            FileStream fs = f.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)
            {
                MessageBox.Show(" Upload failed ", ex.Message.ToString());
            }
        }
        // Download the file 
        private void button2_Click(object sender, EventArgs e)
        {
            string FtpFilePath = "/a.txt";   // Remote path "  "ftp://***.***.***.***:21"; //ftp Server address 

            try
            {
                string LocalPath = "d:\\ftp\\a.txt"; // Download to local path 
                MessageBox.Show(LocalPath);
                if (File.Exists(LocalPath))// Determine whether the file to be downloaded exists ,
                {
                    File.Delete(LocalPath);// If the file exists , Just delete 
                }
                string FTPPath = FTPAddress + FtpFilePath;// original  , Here is the file path of the server （FTPAddress） + The name of the file to be downloaded （FtpFilePath）
                //string FTPPath = FTPAddress + "/" + LocalPath;
                MessageBox.Show(FTPPath);
                // establish ftp Connect 
                FtpWebRequest reqFtp = (FtpWebRequest)FtpWebRequest.Create(new Uri(FTPPath));
                reqFtp.UseBinary = true;
                reqFtp.Credentials = new NetworkCredential(FTPUsername, FTPPwd);
                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);
                // Create and write files 
                FileStream OutputStream = new FileStream(LocalPath, FileMode.Create);
                while (readCount > 0)
                {
                    OutputStream.Write(buffer, 0, buffersize);
                    readCount = ftpStream.Read(buffer, 0, buffersize);
                }
                ftpStream.Close();
                OutputStream.Close();
                response.Close();
                if (File.Exists(LocalPath))
                    MessageBox.Show(" The download ");

            }
            catch (Exception ex)
            {

                MessageBox.Show(ex.Message.ToString());
            }
        }
    }
}