namespace WpfApplication1
{
    delegate void myDelegate(String S);
    public class Serial
    {
        private SerialPort port = new SerialPort("COM3", 115200, Parity.None, 8, StopBits.One);
        String received;
        public event EventHandler Jump;

    //myDelegate delegate1 = new myDelegate(port_DataReceived);

    public Serial()
    {
        port.DataReceived += new SerialDataReceivedEventHandler(port_DataReceived);
        port.Open();
    }

    public void port_DataReceived(object sender, SerialDataReceivedEventArgs e) // serial event
    {
        received += port.ReadExisting();
        Debug.Write(received);
    }
    public void OnJump()
    {
        EventHandler handler = Jump;
        if (null != handler) handler(this, EventArgs.Empty);

        MainWindow yolo = new MainWindow();
        MainWindow.receivedBytes += new EventHandler(port_DataReceived);
    }
}

    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
{
    Serial serial = new Serial();

    public MainWindow()
    {
        InitializeComponent();
    }

    protected void receivedBytes(String S)
    {
        Textblok.Text += S;
    }