using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace zdarzenia
{
    class PrimeFinder
    {
        public delegate void PrimeFoundHandler(MyAsyncCompletedEventArgs args);
        private delegate void PrimeEventHandler(AsyncOperation asyncCallback);
        public event PrimeFoundHandler primeFoundHandler;
        SendOrPostCallback onCompletedCallback;

        public PrimeFinder()
        {
            onCompletedCallback = new SendOrPostCallback(Completed);
        }

        void Completion(int n,AsyncOperation ao)
        {
            MyAsyncCompletedEventArgs e = new MyAsyncCompletedEventArgs(n, new Exception(), false, new { });
            ao.PostOperationCompleted(onCompletedCallback, e);
        }
    
        private void Completed(object state)
        {
            if (primeFoundHandler != null)
                primeFoundHandler((MyAsyncCompletedEventArgs)state);
            Console.WriteLine("completed");
        }

        public bool isPrimal(int n)
        {
            if (n < 2)
                return false;
            for (int i = 2; i < n; i++)
                if (n % i == 0)
                    return false;
            return true;
        }
        public void Find(AsyncOperation ao)
        {
            int n = 10000000;
            while (true)
            {
                if (isPrimal(n))
                    primeFoundHandler.Invoke(new MyAsyncCompletedEventArgs(n, new Exception(),false, new { }));
                n++;
            }
            Completion(n, ao);
        }
        public void FindAsync(int taskID)
        {
            AsyncOperation asOp = AsyncOperationManager.CreateOperation(taskID);
            PrimeEventHandler primeEventHandler = new PrimeEventHandler(Find);
            primeEventHandler.BeginInvoke(asOp, null, null);
        }
    }
}





////////////////////////


using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace zdarzenia
{
    
    class Program
    {
        private static void newPrime(MyAsyncCompletedEventArgs args)
        {
            Console.WriteLine(args.N + "is prime!");
        }
        static void Main(string[] args)
        {
            PrimeFinder primeFinder = new PrimeFinder();
            primeFinder.primeFoundHandler += newPrime;
            primeFinder.Find();
           
        }
    }
}


/////////////



using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace zdarzenia
{
    class MyAsyncCompletedEventArgs : AsyncCompletedEventArgs
    {
        public int N { get; set; }
        public MyAsyncCompletedEventArgs(int n, Exception e, bool cancelled, object state) : base(e,cancelled,state)
        {
            N = n;
        }
    }
}