Question

Hello guys I have a question regardless a old code a client needed a update.

This code add a thread.sleep(500) to keep the service alive, is reading from a com port some calls, and sending a alarm to other pcs now this time when I was sending some information to the machine in question this error pops out

Cross-thread operation not valid: Control ‘textBox1’ accessed from a thread other than the thread it was created on.

    private void port_DataReceived(object sender, SerialDataReceivedEventArgs e) {
        Thread.Sleep(500);
        string data = port.ReadExisting();
        //try
        //{
            if (textBox1.TextLength == 30000)
            {
                textBox1.Text = "";
            }
        //}
        //catch (Exception) {}
        this.BeginInvoke(new setTextDeleg(si_DataRecived), new object[]{
        data});
    }

This is the function that writes on the com machine, does making a exception to eat the error is ok, or is there another better way to handle it?

PD: Sorry for my bad english, this is on C# 2008 vs

Answer 1

You should modify GUI components like textboxes and labels only from the thread that created them which is the main thread. You may take a look at BackgroundWorker which simplifies this task in WinForms application. And here’s another useful article illustrating the usage of the InvokeRequired property and the Invoke method.