Updating Progress Bar from Thread in C#

Question

    public class Consumer
    {
        Queue<int> queue;
        Object lockObject;

        public Consumer(Queue<int> queue, Object lockObject)
        {
            this.queue = queue;
            this.lockObject = lockObject;
        }

        public void consume(string filepath)
        {
            int item = 0;


            while (true)
            {
                lock (lockObject)
                {
                    if (queue.Count == 0)
                    {
                        Monitor.PulseAll(lockObject);
                        continue;
                    }

                    item = queue.Dequeue();
                    if (item == 0)
                    {
                        break;
                    }

                   //do some staff
                }

            }

        }
    }




    public class Producer 
    {
        Queue<int> queue;
        Object lockObject;

        public int ProgressPercent = 0;
        int TotalProducedElements = 0;
        public bool check1 = false;

        public Producer(Queue<int> queue, Object lockObject)
        {
            this.queue = queue;
            this.lockObject = lockObject;
        }

        private bool IsPrime(int num)
        {
            if (num == 0)
                return true;
            num = Math.Abs(num);
            for (int i = 2; i <= Math.Sqrt(num); i++)
                if (num % i == 0)
                    return false;
            return true;
        }

        public void produce(int target)
        { 
            try
            {
                int seq = 0;
                while (seq++ < target)
                {

                    lock (lockObject)
                    {
                        int item = seq;
                        if (IsPrime(item))
                        {
                            queue.Enqueue(item);

                        }
                        TotalProducedElements++;

                        ProgressPercent = seq;

                        if (queue.Count == 0)
                        {
                            Monitor.PulseAll(lockObject);
                        }
                    }
                }
                queue.Enqueue(0);
              }
            catch (Exception e)
            {
            }

        }
    }
}

 private void Start_Click(object sender, EventArgs e)
    {           

                    Object lockObj = new object(); 

                    Queue<int> queue = new Queue<int>();  

                    Producer p = new Producer(queue, lockObj);

                    Consumer c = new Consumer(queue, lockObj);



                    int target = int.Parse(TargetText.Text);
                    string path = Path.Text;

                    Thread Thread1 = new Thread(() => p.produce(target));
                    Thread Thread2 = new Thread(()=>c.consume(path));

                    Thread1.Start();



                    Thread2.Start();
                   progressBar1.Maximum = target;

                  while(true)
                       {
                         if(p.ProgressPercent==0)
                            {
                               Thread.sleep(1000);
                            }
                            else
                             {
                               progressBar1.Value=p.ProgressPercent;
                             }

                        }

                 }

I have two classes working on same queue. one to produce a set of integers and the second is to consume that integers from queue.

And during all this I want to update my progress bar by that percentage. So how to update progress bar from consumer without blocking for my GUI?

Note I have used progressbar.Invoke and delegate but didn't work.

Answer 1

You need two things. First is obviously a thread, the other is invoker.

Invokers will let you change window's controls from inside of a thread. Here's the example:

Invoke((MethodInvoker)delegate
{
    Label1.text = "asd";
}

Threads are ran like this:

some_thread = new Thread
(delegate()
{

    {
        //some_thread code
    }
});
some_thread.Start();

You also need to add using System.Threading; at the beginning of the file.

So, the final code should look like this:

some_thread = new Thread
(delegate()
{

    {
        for(;;)
        {
                Invoke((MethodInvoker)delegate
                {
                                //update the progress bar here
                }
        }
    }
});
some_thread.Start();

Answer 2

You could use a BackgroundWorker (System.ComponentModel) to accomplish this easily. Take a look at: http://www.codeproject.com/Tips/83317/BackgroundWorker-and-ProgressBar-demo