The problem of waking up existing threads in the ThreadPool

Question

I need help with this code, so if anyone is willing to help I would appreciate it.

I've created a simple thread pool, which is passed an array of numbers, and for each number the threads need to calculate the factorial of that number. What is the problem for me, if I created a thread pool of 2 threads, the first thread will execute the first task and the second thread will execute the second task, what is the problem is that those threads don't wake up to execute all the tasks if there are more than two tasks in the specific case, the problem is that I don't know how to reawaken the threads and how to make them continue to execute tasks as long as there are tasks?

Here is my code:

Class MyThreadPool:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ThreadPool
{
    public class MyThreadPool
    {
        private bool _disposed = false;
        private object _lock = new object();
        private Queue<MyTask> tasks = new();
        private List<Thread> threads = new();
        public MyThreadPool(int numThreads = 0)
        {
            
            for (int i = 0; i < numThreads; i++)
            {
                new Thread(() =>
                {
                    threads.Add(Thread.CurrentThread);
                    if (_disposed == false)
                    {
                        MyTask task = null;
                        lock (_lock)
                        {

                            if (tasks.Count > 0)
                            {
                                task = tasks.Dequeue();

                            }
                            else
                                _disposed = true;

                            if (task != null)
                            {
                                Console.WriteLine($"Thread {Thread.CurrentThread.ManagedThreadId} calculated factorial for {task.getNum()}. Result: {task.CalculateFactoriel(task.getNum())}");
                                Thread.Sleep(1000);
                            }
                            else
                            {
                                Thread.Sleep(1000);

                            }
                        }

                    }


                }).Start();
            }
       
        }
        public void Enqueue(int number)
        {
            tasks.Enqueue(new MyTask(number));
        }
        public void Dispose()
        {
            if (_disposed == true)
            {
                foreach (Thread thread in threads)
                {
                    thread.Join();
                }
            }
        }

    }
}

Class MyTask:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ThreadPool
{
    public class MyTask
    {
        private int num;
        public void setNum(int num)
        {
            this.num = num;
        }
        public int getNum()
        {
            return this.num;
        }
        public MyTask(int number)
        {
            this.num = number;
            
        }
        public int CalculateFactoriel(int number)
        {
            int result = 1;
            for (int i = number; i > 0; i--)
            { 
                result = result * i;
            }
            return result;
        }

    }
}

Program.cs:

int[] array = { 1, 2, 3, 4, 5, 6 };
int numThread = 2;
int x = 0;
MyThreadPool threadPool = new(numThread);
for (int i = 0; i < array.Length; i++)
{
    threadPool.Enqueue(array[i]);

}
while (x != array.Length) ;


threadPool.Dispose();