How let a class send a signal to the main class

Bas Knippels

9y934

The question is about the serial class. One of the class's methods is void port_dataReceived(). This function is a serial event and get triggered when a byte is received over the serial port.

This byte must be processed in the rest of the code. Right now I can acces it with a pushbutton and that works but I need to this to work automatically.

The bytes can contain instructions which places text on the userinterface. For instance "Textblok.Text += received_byte;"

How can I let the serial class add the byte in the the textblock?

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Diagnostics;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.IO.Ports;
class Serial
{
private SerialPort port = new SerialPort("COM3", 115200, Parity.None, 8, StopBits.One);
String received;
public Serial()
{
port.DataReceived += new SerialDataReceivedEventHandler(port_DataReceived);
port.Open();
}
public void port_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
received = port.ReadExisting();
Debug.Write(received);
}
public String getReceived()
{
return received;
}
}
namespace WpfApplication1
{
///
/// Interaction logic for MainWindow.xaml
///
public partial class MainWindow : Window
{
Serial serial = new Serial();
public MainWindow()
{
InitializeComponent();
}
private void pagedown_Click(object sender, RoutedEventArgs e)
{
Textblok.Text = serial.getReceived();
Debug.Write("hello world");
}
private void menu_Click(object sender, RoutedEventArgs e)
{
}
private void pageup_Click(object sender, RoutedEventArgs e)
{
}
private void stop_Click(object sender, RoutedEventArgs e)
{
}
private void step_Click(object sender, RoutedEventArgs e)
{
}
private void start_Click(object sender, RoutedEventArgs e)
{
}
}
}

2 Replies

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Bas Knippels9y ago
I cannot acces the UI elements from the serial Class, that is the entire problem. I will update the code now. The only thing I am trying is to read in a byte and display it on the UI.

So far I have given the advise to use a class, delegates and now I am trying to using a new event. The problem now is that is crashes when I receive a byte
namespace WpfApplication1
{



    public class ReceivedEventArgs : EventArgs
    {
        public string Text { get; }
        public ReceivedEventArgs(string text)
        {
            Text = text;
        }
    }




    public class Serial
    {
        private SerialPort port = new SerialPort("COM3", 115200, Parity.None, 8, StopBits.One);

        public event EventHandler Received;
        protected void OnReceived(string text) =>
        Received?.Invoke(this, new ReceivedEventArgs(text));

        //myDelegate delegate1 = new myDelegate(port_DataReceived);

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

        public void port_DataReceived(object sender, SerialDataReceivedEventArgs e) =>
                OnReceived(port.ReadExisting());
    }




    public partial class MainWindow : Window
    {
        readonly Serial serial = new Serial();

        public MainWindow()
        {
            InitializeComponent();
            serial.Received += (s, e) =>
            Textblok.Text = e.Text; // <-- crashes here
        }

        protected void receivedBytes(String S)
        {
            //serial.Received += (s, e) =>
            //Textblok.Text = e.Text;
        }
}
}
"
An unhandled exception of type 'System.InvalidOperationException' occurred in WindowsBase.dll
Aditional information: The summoning-thread can't open this object because it is property of a different thead.
"
Nilesh Shah9y ago
what is the code in SerialDataReceivedEventHandler?
this one should execute when a byte is received, try to put a message box here to see if it gets fired, if it gets, then your code to assign it to textbox can be written here