CancellationTokenSource cancellationTokenSource = new CancellationTokenSource();

Task.Factory.StartNew(() =>

{

    Thread.Sleep();

    cancellationTokenSource.Cancel();

    Console.WriteLine("Token cancelled");

});

ParallelOptions parallelLoopOptions =

    new ParallelOptions()

    {

        CancellationToken = cancellationTokenSource.Token

    };

try

{

    Parallel.For(, Int64.MaxValue, parallelLoopOptions, index =>

    {

        double result = Math.Pow(index, );

        Console.WriteLine("Index {0}, result {1}", index, result);

        Thread.Sleep();

    });

}

catch (OperationCanceledException)

{

    Console.WriteLine("Cancellation exception caught!");

}