How to send a file from one computer to another computer using C#

private void Form1_Load(object sender, EventArgs e)
        {
            //IPHostEntry IPHost = Dns.GetHostByName(Dns.GetHostName());
            //lbl_Status.Text = "My IP address is " + IPHost.AddressList[0].ToString();
            nSockets = new ArrayList();
            Thread thdListener = new Thread(new ThreadStart(ListenerThread));
            thdListener.Start();
        }

        public void ListenerThread()
        {
            TcpListener tcpListener = new TcpListener(IPAddress.Parse(GetIp()),8080);
            tcpListener.Start();
           
            while (true)
            {
                Socket handlerSocket = tcpListener.AcceptSocket();
                //TcpClient client = tcpListener.AcceptTcpClient();
                //MessageBox.Show(client.Client.RemoteEndPoint + ".");
                if (handlerSocket.Connected)
                {  
                    lb_Connections.Invoke((MethodInvoker)delegate 
                    {
                        //btn_SaveFile.PerformClick();
                        saveFileDialog_Server.ShowDialog();
                        txt_SaveFile_Location.Text = saveFileDialog_Server.FileName;
                        lb_Connections.Items.Add(handlerSocket.RemoteEndPoint.ToString() + " connected.");
                    });
                        
                    lock (this)
                    {
                        nSockets.Add(handlerSocket);
                    }
                    ThreadStart thdstHandler = new ThreadStart(handlerThread);
                    Thread thdHandler = new Thread(thdstHandler);
                    thdHandler.Start();
                }
            }
        }
        public void handlerThread()
        {
            Socket handlerSocket = (Socket)nSockets[nSockets.Count - 1];
            NetworkStream networkStream = new NetworkStream(handlerSocket);
            int thisRead = 0;
            int blockSize = 1024;
            Byte[] dataByte = new Byte[blockSize];
            lock (this)
            {
                // Only one process can access
                // the same file at any given time
                 Stream fileStream = File.OpenWrite(txt_SaveFile_Location.Text);
                while (true)
                {
                    thisRead = networkStream.Read(dataByte, 0, blockSize);
                    fileStream.Write(dataByte, 0, thisRead);
                    if (thisRead == 0) break;
                }
                fileStream.Close();
            }

            lb_Connections.Invoke((MethodInvoker)delegate
            {
                lb_Connections.Items.Add("File Written");
            });
            
            handlerSocket = null;
        }
        public string GetIp()
        {
            string name = Dns.GetHostName();
            IPHostEntry entry = Dns.GetHostEntry(name);
            IPAddress[] addr = entry.AddressList;
            if (addr[1].ToString().Split('.').Length == 4)
            {
                return addr[1].ToString();
            }
            return addr[2].ToString();
        }

private void button1_Click(object sender, EventArgs e)
       {
           DialogResult dialogResult =folderBrowserDialog_openFiles.ShowDialog();
           txt_OpenFiles.Text = folderBrowserDialog_openFiles.SelectedPath;
           filepath = txt_OpenFiles.Text;
       }

       private void button2_Click(object sender, EventArgs e)
       {
           try
           {
               saveFileDialog_zip.Filter = @"Zip Files (.zip) | *.zip | All Files(*.*) | *.*";
               DialogResult dr = saveFileDialog_zip.ShowDialog();
               saveFile = saveFileDialog_zip.FileName;
               fileName = saveFile;
               ZipFile.CreateFromDirectory(filepath, fileName);
               MessageBox.Show("Zip File Created at your Saved Location");
           }

           catch (Exception exception)
           {
               MessageBox.Show("Zip file not created");
           }
       }

       private void btn_Browse_Zip_Click(object sender, EventArgs e)
       {

           DialogResult drbrowse_zip=openFileDialog_OpenZip.ShowDialog();
           openFileDialog_OpenZip.Filter = "Zip Files (.zip) | *.zip | All Files(*.*) | *.*";
           openFileDialog_OpenZip.FilterIndex = 1;
           if (drbrowse_zip == System.Windows.Forms.DialogResult.OK)
           {
                   txt_BrowseZip.Text = openFileDialog_OpenZip.FileName;
           }
       }

       private void btn_Transfer_Click(object sender, EventArgs e)
       {

           Stream fileStream = File.OpenRead(txt_BrowseZip.Text);
           // Alocate memory space for the file
           byte[] fileBuffer = new byte[fileStream.Length];
           fileStream.Read(fileBuffer, 0, (int)fileStream.Length);
           // Open a TCP/IP Connection and send the data
           TcpClient clientSocket=new TcpClient(txt_Server.Text,8080);
           NetworkStream networkStream = clientSocket.GetStream();
           networkStream.Write(fileBuffer, 0, fileBuffer.GetLength(0));
           networkStream.Close();
       }