How to delay in DataReceivedHandler from Arduino to WPF

have the Arduino who send the data continuously without caring the delay and i want to put the delay on my display in C#, so i can print all the value without missing a thing but in every line i want to put a delay for (let say) two seconds. I did with Thread.Sleepsomehow it blocked and delayed my UI and Task.Delay won't help. Does anyone knows how to fix this? unionwells france

My code :

 private SerialPort mySerialPort;
    private readonly StreamWriter sw = new(@"D:\MAAT\readcoba.csv");
    public MainWindow()
    {
        InitializeComponent();
        Configure();
    }

    private void Configure()
    {
        mySerialPort = new(Port())
        {
            BaudRate = 9600,
            Parity = Parity.None,
            StopBits = StopBits.One,
            DataBits = 8,
        };
        mySerialPort.DataReceived += DataReceivedHandler;
        mySerialPort.Open();
    }

    private string Port()
    {
        string port = "";
        string[] ports = SerialPort.GetPortNames();
        foreach (string x in ports)
        {
            port = x;
        }
        return port;
    }

    private async void DataReceivedHandler(
        object sender,
        SerialDataReceivedEventArgs e)
    {
        // It's still not work
        await Task.Delay(2000);
        string indata = mySerialPort.ReadExisting();
        string[] arrData = indata.Split(',');
      
        Application.Current.Dispatcher.Invoke(() =>
        {
            foreach (string item in arrData)
            {
                raw_data_label.Content = raw_data_label.Content.ToString().Contains("Nothing to Display") ?
                $"{item}" : $"{raw_data_label.Content}" + $"{item}";
            }
            sw.WriteLine(indata);
        });
    }

    private void WindowClosed(object sender, EventArgs e)
    {
        sw.Close();
        mySerialPort.Close();
    }
}

Your post was MOVED to its current location as it is more suitable.

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in general, there shouldn't be a delay in the function receiving data

Instead of invoking the UI thread (which you don't have the control te limit). Put the data into a variable/field and use a DispatcherTimer to display it. This way you control the update speed on the screen.

Here's an example:

private SerialPort mySerialPort;
private readonly StreamWriter sw = new(@"D:\MAAT\readcoba.csv");

// create a dispatcher timer
private DispatcherTimer timer = new DispatcherTimer(TimeSpan.FromMilliseconds(200), DispatcherPriority.Normal, UpdateLabel, Dispatcher.CurrentDispatcher)

// a lock object to use threadsafe object access
private object lockObject = new Object();

private static void UpdateLabel(object sender, EventArgs e)
{
    // never update UI within a lock (which is used on other threads)
    // Create a copy or if the field is only written (on the other end) copy the reference.

    string[] data;

    lock(lockObject)
        data = _arduinoData; // You don't need to create a copy, but that's only because the _arduinoData isn't used.
    
    foreach (string item in data)
    {
        // ????? why write to the same label over and over? Rather use a StringBuilder
        raw_data_label.Content = raw_data_label.Content.ToString().Contains("Nothing to Display") ?
        $"{item}" : $"{raw_data_label.Content}" + $"{item}";
    }
}

public MainWindow()
{
    InitializeComponent();
    Configure();
}

private void Configure()
{
    mySerialPort = new(Port())
    {
        BaudRate = 9600,
        Parity = Parity.None,
        StopBits = StopBits.One,
        DataBits = 8,
    };
    mySerialPort.DataReceived += DataReceivedHandler;
    Thread.Sleep(2000);
    mySerialPort.Open();
}

private string Port()
{
    string port = "";
    string[] ports = SerialPort.GetPortNames();
    foreach (string x in ports)
    {
        port = x;
    }
    return port;
}

private string[] arduinoData;

private void DataReceivedHandler(
    object sender,
    SerialDataReceivedEventArgs e)
{
    // It's still not work
    // await Task.Delay(2000);  <-- don't delay here!
    string indata = mySerialPort.ReadExisting();
    string[] arrData = indata.Split(',');

    sw.WriteLine(indata);

    // lock and assigny the reference to the field (this is only allowed when the reference isn't used anymore _(if the string array isn't yours, Use a ToArray to create a copy)_
    // That's why the s.WriteLine(..) is move above this.
    lock(lockObject)
        arduinoData = arrData;
  
}

private void WindowClosed(object sender, EventArgs e)
{
    sw.Close();
    mySerialPort.Close();