C#

Observable.Range(0, 5)
    // Take the Observable off the UI thread
    .SubscribeOn(Scheduler.Default)
    //Create parallel tasks and report results when completed
    .SelectMany(x => Task.Run<FreqValues>(() => DoTaskWork(x), ctr.Token))
    // Switch back to the UI thread
    .ObserveOnDispatcher()
    .Subscribe(args => {
        //Update the progressbar when a thread is completed
        pgbProgress.Value += 1;
        //Tell me what thread is completed
        txtText.Text += Environment.NewLine + args.Frequency.ToString();
    },
    () => {
        //All done, here I could do sorting etc.
        txtText.Text += Environment.NewLine + "All done";
          }
    );

Microsoft Visual Studio Community 2013
Version 12.0.31101.00 Update 4
Microsoft .NET Framework
Version 4.6.01038

Installed Version: Professional

namespace ANameSpace
{
    [ToolboxItem(false)]
    public partial class ValidatingBase<T> : UserControl
    {
        public ValidatingBase()
        {
            InitializeComponent();

    // and so forth

namespace ANameSpace
{
    [ToolboxItem(true)]
    public partial class PersonValidator : ValidatingBase<Person>
    {
        public PersonValidator()
        {
            InitializeComponent();

    // and so forth

Observable.Range(0, 10).
    Select(e => (Task.Factory.StartNew(() => DoWork(e),
                                            CancellationToken.None,
                                            TaskCreationOptions.DenyChildAttach,
                                            TaskScheduler.Default)))
    .ObserveOnDispatcher()
    .Subscribe(evt =>
    {
       //Do something with evt.Result
    });

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Text;

namespace OddNumbers
{
    class Program
    {
        static void Main(string[] args)
        {
            WriteNumbers(EvenNumbers(100, 1000), 10);
            Console.ReadKey();

            WriteNumbers(OddNumbers(100, 1000), 10);
            Console.ReadKey();
        }

        static void WriteNumbers(IEnumerable<int> numbers, int numbersPerLine)
        {
            Debug.Assert(numbers != null);
            Debug.Assert(numbersPerLine >= 1);

            StringBuilder line = new StringBuilder();
            int count = 0;

            Action writeLine = () =>
            {
                Console.WriteLine(line.ToString());
                line.Clear();
                count = 0;
            };

            foreach (int number in numbers)
            {
                line.Append(number).Append(", ");

                count++;

                if (count == numbersPerLine)
                    writeLine();
            }

            if (count > 0)
                writeLine();
        }

        static IEnumerable<int> EvenNumbers(int start, int end)
        {
            Debug.Assert(start <= end);

            if (IsOdd(start))
                start++;

            for (int i = start; i <= end; i += 2)
                yield return i;
        }

        static IEnumerable<int> OddNumbers(int start, int end)
        {
            Debug.Assert(start <= end);

            if (!IsOdd(start))
                start++;

            for (int i = start; i <= end; i += 2)
                yield return i;
        }

        static bool IsOdd(int number)
        {
            return (number & 1) == 1;
        }
    }
}