using System;

using System.Collections.Concurrent;

using System.Collections.Generic;

using System.Linq;

using System.Threading.Tasks;

using System.Threading;

​

public class Program

{

    public static void Main()

    {

        List<string> names = new List<string>();

        for (int i = 1; i <= 500000; i++)

        {

            names.Add("jKlaus");

        }

        var count=0;

​

        // https://msdn.microsoft.com/en-us/library/dd997393(v=vs.110).aspx

        Parallel.ForEach(names,

            () => 0, // initial value

            (name, loop, subtotal) =>

            {

                subtotal += 1;

                // subtotal is modified and returned

                return subtotal;

            },

            // update the count with the result of all of the +1 to subtotal

            finalResult => Interlocked.Add(ref count, finalResult));

        Console.WriteLine("List Count: "+names.Count());

        Console.WriteLine("Parallel Count: "+count);

    }

}