.NET: How to have background thread signal main thread data is available?

private static BackgroundWorker worker = new BackgroundWorker();
    static void Main(string[] args)
    {
        worker.DoWork += worker_DoWork;
        worker.RunWorkerCompleted += worker_RunWorkerCompleted;
        worker.ProgressChanged += worker_ProgressChanged;
        worker.WorkerReportsProgress = true;

        Console.WriteLine("Starting application.");
        worker.RunWorkerAsync();

        Console.ReadKey();
    }

    static void worker_ProgressChanged(object sender, ProgressChangedEventArgs e)
    {
        Console.WriteLine("Progress.");
    }

    static void worker_DoWork(object sender, DoWorkEventArgs e)
    {
        Console.WriteLine("Starting doing some work now.");

        for (int i = 0; i < 5; i++)
        {
            Thread.Sleep(1000);
            worker.ReportProgress(i);
        }
    }

    static void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
        Console.WriteLine("Done now.");
    }

using System;
using System.Collections.Generic;
using System.Threading;

namespace ConsoleApplication1
{
    class Program
    {
        private static object LockObject = new Object();

    private static AutoResetEvent _flag;
    private static Queue<int> _list;

    static void Main(string[] args)
    {
        _list = new Queue<int>();
        _flag = new AutoResetEvent(false);

        ThreadPool.QueueUserWorkItem(ProducerThread);

        int itemCount = 0;

        while (itemCount < 10)
        {
            if (_flag.WaitOne(0))
            {
                // there was an item
                lock (LockObject)
                {
                    Console.WriteLine("Items in queue:");
                    while (_list.Count > 0)
                    {
                        Console.WriteLine("Found item {0}.", _list.Dequeue());
                        itemCount++;
                    }
                }
            }
            else
            {
                Console.WriteLine("No items in queue.");
                Thread.Sleep(125);
            }
        }
    }

    private static void ProducerThread(object state)
    {
        Random rng = new Random();

        Thread.Sleep(250);

        for (int i = 0; i < 10; i++)
        {
            lock (LockObject)
            {
                _list.Enqueue(rng.Next(0, 100));
                _flag.Set();
                Thread.Sleep(rng.Next(0, 250));
            }
        }
    }
}

private static AutoResetEvent _flag;
    private static Queue<int> _list;

    static void Main(string[] args)
    {
        _list = new Queue<int>();
        _flag = new AutoResetEvent(false);

        ThreadPool.QueueUserWorkItem(ProducerThread);

        int itemCount = 0;

        while (itemCount < 10)
        {
            if (_flag.WaitOne(0))
            {
                // there was an item
                lock (LockObject)
                {
                    Console.WriteLine("Items in queue:");
                    while (_list.Count > 0)
                    {
                        Console.WriteLine("Found item {0}.", _list.Dequeue());
                        itemCount++;
                    }
                }
            }
            else
            {
                Console.WriteLine("No items in queue.");
                Thread.Sleep(125);
            }
        }
    }

    private static void ProducerThread(object state)
    {
        Random rng = new Random();

        Thread.Sleep(250);

        for (int i = 0; i < 10; i++)
        {
            lock (LockObject)
            {
                _list.Enqueue(rng.Next(0, 100));
                _flag.Set();
                Thread.Sleep(rng.Next(0, 250));
            }
        }
    }
}

AutoResetEvent ev = new AutoResetEvent(false);
...
if(ev.WaitOne(0, false)) {
  // event happened
}
else {
 // do other stuff
}

this.asyncOperation = AsyncOperationManager.CreateOperation(null);
this.asyncOperation.Post(delegateMethod, arg);