Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim server As TcpListener = Nothing
        Try
            ' Setto la Porta i ascolto 
            Dim port As Int32 = 9999
            ' Setto l'IP del Server
            Dim IpLocal As String = "127.0.0.1"
            Dim localAddr As IPAddress = IPAddress.Parse(IpLocal)
            ' TcpListener server = new TcpListener(port);
            server = New TcpListener(localAddr, port)
            ' Start listening for client requests.
            server.Start()
            ' Buffer for reading data
            Dim bytes As Byte() = Nothing
            Dim data As String = Nothing
            Dim ClientList As List(Of TcpClient) = Nothing
            ' Enter the listening loop.
            TextBox1.AppendText("Waiting for a connection... ")
            Do
                If server.Pending Then
                    Dim client As TcpClient = server.AcceptTcpClient()
                    MsgBox("ciao")
                    ClientList.Add(client)
                    TextBox1.AppendText("Connected!")
                    data = Nothing
                    Dim stream As NetworkStream = client.GetStream()
                    Dim i As Integer
                    While Not ((i = stream.Read(bytes, 0, 256)) = 0)
                        data = System.Text.Encoding.ASCII.GetString(bytes, 0, i)
                        TextBox1.AppendText("Sent: " & data)
                        data = data.ToUpper()
                        Dim msg As Byte() = System.Text.Encoding.ASCII.GetBytes(data)
                        stream.Write(msg, 0, msg.Length)
                        TextBox1.AppendText("Sent: " & data)
                    End While
                    client.Close()
                End If
            Loop
        Catch ex As Exception
            Console.WriteLine("SocketException: {0}", e)
        Finally
            server.Stop()
        End Try
    End Sub