ThreadPool class is used to manage a set of readily available threads to be used by a process. We can use ThreadPool class for creating threads when we require large number of short living threads. A short living thread is a thread that is created to perform a single task and then terminated.We can use ThreadPool class when it is not necessary to have full control over each individual threads.

Note: There is a limit of 25 threads in a thread pool. That means if you
start 50 threads then only 25 threads is active at a time. As soon as a
thread finishes another thread is active from thread pool.
Avoiding uses of ThreadPool class when following situation raise
1.       Requires a foreground thread.
2.       Requires a thread to have a particular priority.

3.       Have task that can block threads for long period of time. The threadpool has a maximum number of threads, so a large number of threadsfrom the thread pool being blocked might prevent task from starting.

4.       Need to have stable identity associated with thread.
5.       Need to place threads into a single threaded apartment.
Implementation of ThreadPool class


using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
namespace ThreadStartDemo
    class ThreadPoolClassDemo
        static void Main(string[] args)
            //Call QueueUserWorkItem method of ThreadPool claas
            //to send Thread in ThreadPool and pass object of
            //WaitCallback deleaget.
            ThreadPool.QueueUserWorkItem(new WaitCallback(ThreadProc));
            Console.WriteLine("Main Thread Started.");
            Console.WriteLine("Main Thread Exists.");
        /// <summary>
        /// This method is passed to WaitCallback delegate.
        /// This method is used to print numbers from 1 to 50.
        /// Main thread exists in two case either time fiven in main sleep
        /// method over of number is printed from 1 to 50.
        /// </summary>
        /// <param name="stateInfo"></param>
        static void ThreadProc(object stateInfo)
            Console.WriteLine("Welcome from thread pool. I will count from 1 to 50");
            for (int i = 1; i <= 50; i++)

Execute above program to see the output.

  Modified On Sep-18-2014 01:24:02 PM

Leave Comment