I used "lock" in the "task it doesn't work and race condition occurred

Question

I used "lock" in the "task" it doesn't work and race condition occurred

I have defined a Counter, which should eventually return 0, because a Method increases the value of the Counter and a Method decreases it.

And when I use Thread it is not a problem. This problem occurs when I use Task

I use lock and monitor But it did not work again and gave the same result as before

namespace ConsoleApp1
{
    public class LockDemo
    {
        private readonly static object _lock = new object();
        private static int _count = 0;
        public void Main()
        {
            var tasks = new List<Task>();
            for (int i = 0; i < 1000; i++)
            {
                tasks.Add(new Task(() => IncrementCounter()));
                tasks.Add(new Task(() => DecrementCounter()));
            }

            foreach (var item in tasks)
            {
                item.Start();
            }
        }
        void IncrementCounter()
        {
            Console.WriteLine("wait for opening lock...");
            lock (_lock)
            {
                Console.ForegroundColor = ConsoleColor.Green;

                Console.WriteLine("enter the critical section");
                _count += 1;
                Console.WriteLine("Counter:" + _count);
                Console.ForegroundColor = ConsoleColor.White;
            }
            Console.WriteLine("exit critical section");
        }
        void DecrementCounter()
        {
            Console.WriteLine("wait for opening lock...");
            lock (_lock)
            {
                Console.ForegroundColor = ConsoleColor.Red;
                Console.WriteLine("enter the critical section");
                _count -= 1;
                Console.WriteLine("Counter:" + _count);
                Console.ForegroundColor = ConsoleColor.White;
            }
            Console.WriteLine("exit critical section");
        }
    }
}

Answer 1

You're creating two thousand tasks: 1,000 increment and 1,000 decrement. Even though you're starting the tasks in a specific order, there's no guarantee they will execute in that order because they're running asynchronously. Its possible for two decrements to happen, and then a single increment, etc. - which is likely what you're seeing here.

Also, it is not recommended to use Task.Start

Regarding usage of Task.Start() , Task.Run() and Task.Factory.StartNew()

https://devblogs.microsoft.com/pfxteam/task-factory-startnew-vs-new-task-start/