Task.WaitAll Method (Task[])

using System;
using System.Threading;
using System.Threading.Tasks;

class WaitAllDemo
{
    // Demonstrated features:
    // 		Task.Factory
    //		Task.Result
    //		Exception handling
    // Expected results:
    // 		10 tasks are started, each passed an index as a state object.
    //		The tasks that receive an argument between 2 and 5 throw exceptions.
    //		Task.WaitAll() wraps all exceptions in an AggregateException and propagates it to the main thread.
    // Documentation:
    //		http://msdn.microsoft.com/en-us/library/system.threading.tasks.taskfactory_members(VS.100).aspx
    static void Main()
    {
        // Define a delegate that prints and returns the system tick count
        Func<object, int> action = (object obj) =>
        {
            int i = (int)obj;

            // Make each thread sleep a different time in order to return a different tick count
            Thread.Sleep(i * 100);

            // The tasks that receive an argument between 2 and 5 throw exceptions
            if (2 <= i && i <= 5)
            {
                throw new InvalidOperationException("SIMULATED EXCEPTION");
            }

            int tickCount = Environment.TickCount;
            Console.WriteLine("Task={0}, i={1}, TickCount={2}, Thread={3}", Task.CurrentId, i, tickCount, Thread.CurrentThread.ManagedThreadId);

            return tickCount;
        };

        const int n = 10;

        // Construct started tasks
        Task<int>[] tasks = new Task<int>[n];
        for (int i = 0; i < n; i++)
        {
            tasks[i] = Task<int>.Factory.StartNew(action, i);
        }

        // Exceptions thrown by tasks will be propagated to the main thread
        // while it waits for the tasks. The actual exceptions will be wrapped in AggregateException.
        try
        {
            // Wait for all the tasks to finish.
            Task.WaitAll(tasks);

            // We should never get to this point
            Console.WriteLine("WaitAll() has not thrown exceptions. THIS WAS NOT EXPECTED.");
        }
        catch (AggregateException e)
        {
            Console.WriteLine("\nThe following exceptions have been thrown by WaitAll(): (THIS WAS EXPECTED)");
            for (int j = 0; j < e.InnerExceptions.Count; j++)
            {
                Console.WriteLine("\n-------------------------------------------------\n{0}", e.InnerExceptions[j].ToString());
            }
        }
    }

}