class Program
    {
        static void Main(string[] args)
        {
            var data = new List<int> { 1, 2 };
            for (int i = 0; i < 100; i++)
            {
                data.Add(1);
            }
            NewMethod1(data);
            NewMethod(data);
            Console.Read();
        }

        private static void NewMethod1(List<int> data)
        {
            Parallel.ForEach(data, index =>
            {
                Parallel.ForEach(data, item =>
                {
                    Console.WriteLine(item * index);
                });

            });
        }

        private static void NewMethod(List<int> data)
        {
            Parallel.ForEach(data, index =>
            {
                var taskFactory = new TaskFactory(TaskCreationOptions.AttachedToParent, TaskContinuationOptions.ExecuteSynchronously);
                var childTasks = new List<Task>();
                Task parentTask = new Task(() =>
                {
                    foreach (var i in data)
                    {
                        var tmp = i;
                        var childTask = taskFactory.StartNew(() =>
                        {
                            Console.WriteLine(i * index);
                        });
                        childTasks.Add(childTask);
                    }
                });
                parentTask.Start();
                parentTask.Wait();
            });
        }
    }