C#/.NET - max and min number of threads in thread pool

To set up max and min number of threads in ThreadPool class, ThreadPool.SetMinThreads and ThreadPool.SetMaxThreads methods could be useful.

1. Max and min number of threads example

using System;
using System.Threading;

namespace Test
{
	public class Program
	{
		static void Main(string[] args)
		{
			int tasksCount = 5;
			int iterationsCount = 5;

			WaitCallback callback = (object state) =>
			{
				int taskId = (int)state;

				for (int i = 0; i < iterationsCount; ++i)
				{
					int iterationId = i + 1;

					Console.WriteLine("Task " + taskId + "/" + tasksCount 
						+ ": Iteration " + iterationId + "/" + iterationsCount);
				}
			};

			ThreadPool.SetMinThreads(1, 1);
			ThreadPool.SetMaxThreads(2, 2);

			for (int i = 0; i < tasksCount; ++i)
			{
				int taskId = i + 1;

				ThreadPool.QueueUserWorkItem(callback, taskId);
			}

			Thread.Sleep(1000);
		}
	}
}

Output:

Task 1/5: Iteration 1/5
Task 2/5: Iteration 1/5
Task 2/5: Iteration 2/5
Task 2/5: Iteration 3/5
Task 1/5: Iteration 2/5
Task 1/5: Iteration 3/5
Task 1/5: Iteration 4/5
Task 1/5: Iteration 5/5
Task 2/5: Iteration 4/5
Task 2/5: Iteration 5/5
Task 3/5: Iteration 1/5
Task 3/5: Iteration 2/5
Task 3/5: Iteration 3/5
Task 3/5: Iteration 4/5
Task 3/5: Iteration 5/5
Task 4/5: Iteration 1/5
Task 4/5: Iteration 2/5
Task 4/5: Iteration 3/5
Task 4/5: Iteration 4/5
Task 4/5: Iteration 5/5
Task 5/5: Iteration 1/5
Task 5/5: Iteration 2/5
Task 5/5: Iteration 3/5
Task 5/5: Iteration 4/5
Task 5/5: Iteration 5/5

 Note: Notice that, only 2 tasks are executed in the same time.

2. Resources

1. ThreadPool Class - Microsoft Docs
2. ThreadPool.SetMinThreads - Microsoft Docs
3. ThreadPool.SetMaxThreads - Micosoft Docs