Parallel.Invoke

ParallelInvoke

namespace ParallelInvoke
{
using System.Threading;
using System.Threading.Tasks;
class Program
{
    static void Main(string[] args)
    {
        Parallel.Invoke(() =>
        {
            Console.WriteLine("Starting first task");
            Console.WriteLine("Thread ID - {0}", Thread.CurrentThread.ManagedThreadId);
            DoFirstTask();
        }, () =>
        {
            Console.WriteLine("Starting second task");
            Console.WriteLine("Thread ID - {0}", Thread.CurrentThread.ManagedThreadId);
            DoSecondTask();
        }, () =>
        {
            Console.WriteLine("Starting third task");
            Console.WriteLine("Thread ID - {0}", Thread.CurrentThread.ManagedThreadId);
            DoThirdTask();
        }
            );
        Console.ReadLine();
    }
    public static void DoFirstTask()
    {
        List<int> numbers = new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
        Console.WriteLine("Total numbers - {0}", numbers.Count());
        Console.WriteLine("First task completed.");
    }
    public static void DoSecondTask()
    {
        List<int> numbers = new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
        Console.WriteLine("Sum of all numbers - {0}", numbers.Sum());
        Console.WriteLine("Second task completed.");
    }
    public static void DoThirdTask()
    {
        List<int> numbers = new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
        Console.WriteLine("Average of all numbers - {0}", numbers.Average());
        Console.WriteLine("Third task completed.");
    }
}
}

ParallelInvokeCancel

namespace ParallelInvokeCancel
{
using System.Threading;
using System.Threading.Tasks;
class Program
{
    static CancellationTokenSource cancelToken = new CancellationTokenSource();
    static void Main(string[] args)
    {
        ParallelOptions options = new ParallelOptions();
        options.CancellationToken = cancelToken.Token;
        try
        {
            Parallel.Invoke(options, () =>
            {
                Console.WriteLine("Starting first task");
                Console.WriteLine("Thread ID - {0}", Thread.CurrentThread.ManagedThreadId);
                DoFirstTask();
            }, () =>
            {
                Console.WriteLine("Starting second task");
                Console.WriteLine("Thread ID - {0}", Thread.CurrentThread.ManagedThreadId);
                DoSecondTask();
                options.CancellationToken.ThrowIfCancellationRequested();
            }, () =>
            {
                Console.WriteLine("Starting third task");
                Console.WriteLine("Thread ID - {0}", Thread.CurrentThread.ManagedThreadId);
                DoThirdTask();
            }
            );
        }
        catch (OperationCanceledException ex)
        {
            Console.ForegroundColor = ConsoleColor.Red;
            Console.WriteLine("Error Message - {0}", ex.Message);
        }
           
        Console.ReadLine();
    }
    public static void DoFirstTask()
    {
        List<int> numbers = new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
        Console.WriteLine("Total numbers - {0}", numbers.Count());
        Console.WriteLine("First task completed.");
    }
    public static void DoSecondTask()
    {
        List<int> numbers = new List<int>();
        if (numbers.Count <= 0)
        {
            cancelToken.Cancel();
            return;
        }
        Console.WriteLine("Sum of all numbers - {0}", numbers.Sum());
        Console.WriteLine("Second task completed.");
    }
    public static void DoThirdTask()
    {
        List<int> numbers = new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
        Console.WriteLine("Average of all numbers - {0}", numbers.Average());
        Console.WriteLine("Third task completed.");
    }
}
}

ParallelInvokeException

namespace ParallelInvoke
{
using System.Collections.Concurrent;
using System.Threading;
using System.Threading.Tasks;
class Program
{
    public static ConcurrentQueue<Exception> exceptionQueue = new ConcurrentQueue<Exception>();
    static void Main(string[] args)
    {
        try
        {
            Parallel.Invoke(() =>
            {
                Console.WriteLine("Starting first task");
                Console.WriteLine("Thread ID - {0}", Thread.CurrentThread.ManagedThreadId);
                DoFirstTask();
            }, () =>
            {
                Console.WriteLine("Starting second task");
                Console.WriteLine("Thread ID - {0}", Thread.CurrentThread.ManagedThreadId);
                DoSecondTask();
                if (exceptionQueue.Count > 0) throw new AggregateException(exceptionQueue);
            }, () =>
            {
                Console.WriteLine("Starting third task");
                Console.WriteLine("Thread ID - {0}", Thread.CurrentThread.ManagedThreadId);
                DoThirdTask();
            }
            );
        }
        catch (AggregateException ex)
        {
            foreach (Exception e in ex.InnerExceptions)
            {
                Console.ForegroundColor = ConsoleColor.Red;
                Console.WriteLine("Error Message - {0}", e.InnerException.Message);
            }
        }
        Console.ReadLine();
    }
    public static void DoFirstTask()
    {
        List<int> numbers = new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
        Console.WriteLine("Total numbers - {0}", numbers.Count());
        Console.WriteLine("First task completed.");
    }
    public static void DoSecondTask()
    {
        List<int> numbers = new List<int>();
        if (numbers.Count <= 0)
        {
            exceptionQueue.Enqueue(new Exception("numbers list is empty"));
        }
        Console.WriteLine("Sum of all numbers - {0}", numbers.Sum());
        Console.WriteLine("Second task completed.");
    }
    public static void DoThirdTask()
    {
        List<int> numbers = new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
        Console.WriteLine("Average of all numbers - {0}", numbers.Average());
        Console.WriteLine("Third task completed.");
    }
}
}

Parallel.Invoke – Task Parallel Library