Question

    private void button1_Click(object sender, EventArgs e)
    {
        PROGRESS_BAR.Minimum = 0;
        PROGRESS_BAR.Maximum = 100;
        PROGRESS_BAR.Value = 0;

        for (int i = 0; i < 100; i++)
        {
            Thread t = new Thread(new ThreadStart(updateProgressBar));
            t.IsBackground = true;
            t.Start();
        }

    }

    private void updateProgressBar()
    {   
          PROGRESS_BAR.PerformStep();
          Thread.Sleep(4000);
    }

I always get this error:
Cross-thread operation not valid: Control ” accessed from a thread other than the thread it was created on.

I tried to search in google for solutions and unfortunately all of them didn’t work for me. does any one know how to solve this?
thanks in advance..

Answer 1

You cannot interact with UI elements from non-UI thread.
You need to use code like

this.BeginInvoke((Action)(() => PROGRESS_BAR.PerformStep()));