Monitor.Enter
using System; using System.Threading; public class EnterExit { private int result = 0; public void NonCriticalSection() { Console.WriteLine("Entered Thread " + Thread.CurrentThread.GetHashCode()); for (int i = 1; i <= 5; i++) { Console.WriteLine("Result = " + result++ + " ThreadID " + Thread.CurrentThread.GetHashCode()); Thread.Sleep(1000); } Console.WriteLine("Exiting Thread " + Thread.CurrentThread.GetHashCode()); } public void CriticalSection() { Monitor.Enter(this); Console.WriteLine("Entered Thread " + Thread.CurrentThread.GetHashCode()); for (int i = 1; i <= 5; i++) { Console.WriteLine("Result = " + result++ + " ThreadID " + Thread.CurrentThread.GetHashCode()); Thread.Sleep(1000); } Console.WriteLine("Exiting Thread " + Thread.CurrentThread.GetHashCode()); Monitor.Exit(this); } public static void Main(String[] args) { EnterExit e = new EnterExit(); Thread nt1 = new Thread(new ThreadStart(e.NonCriticalSection)); nt1.Start(); Thread nt2 = new Thread(new ThreadStart(e.NonCriticalSection)); nt2.Start(); Thread ct1 = new Thread(new ThreadStart(e.CriticalSection)); ct1.Start(); Thread ct2 = new Thread(new ThreadStart(e.CriticalSection)); ct2.Start(); } }