How can i pause/continue backgroundworker?

Question

I have a button click event for continue:

 private void button3_Click(object sender, EventArgs e)
        {
            if (backgroundWorker1.IsBusy)
            {
                button2.Enabled = true;
                button3.Enabled = false;
            }
            else
            {
                backgroundWorker1.RunWorkerAsync();
                button2.Enabled = true;
                button3.Enabled = false;
            }

        }

And a button click event for pausing:

private void button2_Click(object sender, EventArgs e)
        {
            if (backgroundWorker1.WorkerSupportsCancellation == true)
            {
                backgroundWorker1.CancelAsync();
                button3.Enabled = true;
                soundPlay = false;
                stop_alarm = true;
            }

        }

The problem is with the button3 click event the continue code sometimes the background is busy so i can enable false/true the buttons but the backgroundworker is keep working. I want to pause the DoWork event and to continue.

This is my DoWork event:

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            BackgroundWorker worker = sender as BackgroundWorker;
            while (true)
            {
                if ((worker.CancellationPending == true))
                {
                    e.Cancel = true;
                    break;
                }
                else
                {
                    if (tempCpuValue >= (float?)numericUpDown1.Value || tempGpuValue >= (float?)numericUpDown1.Value)
                    {
                        soundPlay = true;
                        blinking_label();
                    }
                    else
                    {
                        soundPlay = false;
                    }
                    cpuView();
                    gpuView();
                    Thread.Sleep(1000);
                }
            }
        }

Answer 1

You may need to wait until cancellation is done before enable/disable button.

private AutoResetEvent _resetEvent = new AutoResetEvent(false);

private void button2_Click(object sender, EventArgs e)
        {
            if (backgroundWorker1.WorkerSupportsCancellation == true)
            {
                backgroundWorker1.CancelAsync();
                //Wait statement goes here.
                this.Cursor=Cursors.AppStarting;
                _resetEvent.WaitOne(); // will block until _resetEvent.Set() call made

                button3.Enabled = true;
                soundPlay = false;
                stop_alarm = true;
            }

        }

Please see this question:

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            BackgroundWorker worker = sender as BackgroundWorker;
            while (true)
            {
                if ((worker.CancellationPending == true))
                {
                    e.Cancel = true;

                    break;
                }
                else
                {
                    if (tempCpuValue >= (float?)numericUpDown1.Value || tempGpuValue >= (float?)numericUpDown1.Value)
                    {
                        soundPlay = true;
                        blinking_label();
                    }
                    else
                    {
                        soundPlay = false;
                    }
                    cpuView();
                    gpuView();
                    Thread.Sleep(1000);
                }
            }

              _resetEvent.Set(); // signal that worker is done
        }

Answer 2

You could do this with a Thread instead of a BackgroundWorker?

With a Thread, in its working subroutine you could put the thread into an infinite sleep inside a try/catch block that catches ThreadInterruptedException. So, as it loops through whatever it's working on, you could look at the value of a boolean flag to know whether or not to sleep, and then call Thread.Sleep(Timeout.Infinite). When you catch ThreadInterruptedException you set the flag to false and continue to execute.

To make the thread resume from your UI, you would set the 'pause' flag to false and call workerThread.Interrupt() on your thread (assuming you called it workerThread, that is).

Idea sourced from here