BlockingCollection<T> Class

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

class BlockingCollectionDemo
{
    static void Main()
    {
        AddTakeDemo.BC_AddTakeCompleteAdding();
        TryTakeDemo.BC_TryTake();
        FromToAnyDemo.BC_FromToAny();
        ConsumingEnumerableDemo.BC_GetConsumingEnumerable();
        Console.WriteLine("Press any key to exit.");
        Console.ReadKey();
    }
}
class AddTakeDemo
{
    // Demonstrates: 
    //      BlockingCollection<T>.Add() 
    //      BlockingCollection<T>.Take() 
    //      BlockingCollection<T>.CompleteAdding() 
    public static void BC_AddTakeCompleteAdding()
    {
        using (BlockingCollection<int> bc = new BlockingCollection<int>())
        {

            // Spin up a Task to populate the BlockingCollection  
            using (Task t1 = Task.Factory.StartNew(() =>
            {
                bc.Add(1);
                bc.Add(2);
                bc.Add(3);
                bc.CompleteAdding();
            }))
            {

                // Spin up a Task to consume the BlockingCollection 
                using (Task t2 = Task.Factory.StartNew(() =>
                {
                    try
                    {
                        // Consume consume the BlockingCollection 
                        while (true) Console.WriteLine(bc.Take());
                    }
                    catch (InvalidOperationException)
                    {
                        // An InvalidOperationException means that Take() was called on a completed collection
                        Console.WriteLine("That's All!");
                    }
                }))

                    Task.WaitAll(t1, t2);
            }
        }
    }
}

class TryTakeDemo
{
    // Demonstrates: 
    //      BlockingCollection<T>.Add() 
    //      BlockingCollection<T>.CompleteAdding() 
    //      BlockingCollection<T>.TryTake() 
    //      BlockingCollection<T>.IsCompleted 
    public static void BC_TryTake()
    {
        // Construct and fill our BlockingCollection 
        using (BlockingCollection<int> bc = new BlockingCollection<int>())
        {
            int NUMITEMS = 10000;
            for (int i = 0; i < NUMITEMS; i++) bc.Add(i);
            bc.CompleteAdding();
            int outerSum = 0;

            // Delegate for consuming the BlockingCollection and adding up all items
            Action action = () =>
            {
                int localItem;
                int localSum = 0;

                while (bc.TryTake(out localItem)) localSum += localItem;
                Interlocked.Add(ref outerSum, localSum);
            };

            // Launch three parallel actions to consume the BlockingCollection
            Parallel.Invoke(action, action, action);

            Console.WriteLine("Sum[0..{0}) = {1}, should be {2}", NUMITEMS, outerSum, (NUMITEMS / 2) * (NUMITEMS - 1));
            Console.WriteLine("bc.IsCompleted = {0} (should be true)", bc.IsCompleted);
        }
    }
}

class FromToAnyDemo
{

    // Demonstrates: 
    //      Bounded BlockingCollection<T> 
    //      BlockingCollection<T>.TryAddToAny() 
    //      BlockingCollection<T>.TryTakeFromAny() 
    public static void BC_FromToAny()
    {
        BlockingCollection<int>[] bcs = new BlockingCollection<int>[2];
        bcs[0] = new BlockingCollection<int>(5); // collection bounded to 5 items
        bcs[1] = new BlockingCollection<int>(5); // collection bounded to 5 items 

        // Should be able to add 10 items w/o blocking 
        int numFailures = 0;
        for (int i = 0; i < 10; i++)
        {
            if (BlockingCollection<int>.TryAddToAny(bcs, i) == -1) numFailures++;
        }
        Console.WriteLine("TryAddToAny: {0} failures (should be 0)", numFailures);

        // Should be able to retrieve 10 items 
        int numItems = 0;
        int item;
        while (BlockingCollection<int>.TryTakeFromAny(bcs, out item) != -1) numItems++;
        Console.WriteLine("TryTakeFromAny: retrieved {0} items (should be 10)", numItems);
    }
}

class ConsumingEnumerableDemo
{
    // Demonstrates: 
    //      BlockingCollection<T>.Add() 
    //      BlockingCollection<T>.CompleteAdding() 
    //      BlockingCollection<T>.GetConsumingEnumerable() 
    public static void BC_GetConsumingEnumerable()
    {
        using (BlockingCollection<int> bc = new BlockingCollection<int>())
        {

            // Kick off a producer task
            Task.Factory.StartNew(() =>
            {
                for (int i = 0; i < 10; i++)
                {
                    bc.Add(i);
                    Thread.Sleep(100); // sleep 100 ms between adds
                }

                // Need to do this to keep foreach below from hanging
                bc.CompleteAdding();
            });

            // Now consume the blocking collection with foreach. 
            // Use bc.GetConsumingEnumerable() instead of just bc because the 
            // former will block waiting for completion and the latter will 
            // simply take a snapshot of the current state of the underlying collection. 
            foreach (var item in bc.GetConsumingEnumerable())
            {
                Console.WriteLine(item);
            }
        }
    }
}