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copied!<p>Take a look at <a href="http://msdn.microsoft.com/en-us/library/system.threading.autoresetevent.aspx" rel="nofollow noreferrer">AutoResetEvent</a> and <a href="http://msdn.microsoft.com/en-us/library/system.threading.manualresetevent.aspx" rel="nofollow noreferrer">ManualResetEvent</a>. They are signals that makes synchronisation between threads possible.</p> <p>The first thread that needs to wait for something to get done will do myEvent.<a href="http://msdn.microsoft.com/en-us/library/58195swd.aspx" rel="nofollow noreferrer">WaitOne</a>(), which blocks until the other thread calls myEvent.<a href="http://msdn.microsoft.com/en-us/library/system.threading.eventwaithandle.set.aspx" rel="nofollow noreferrer">Set</a>().</p> <p>Let's say we have two threads, where one of them needs to do some kind of initialisation before the other thread can continue. You then share a AutoResetEvent between the two, let's call it myEvent.</p> <pre><code>// Signal example using System; using System.Threading; class MySync { private readonly AutoResetEvent _myEvent; public MySync(AutoResetEvent myEvent) { _myEvent = myEvent; } public void ThreadMain(object state) { Console.WriteLine("Starting thread MySync"); _myEvent.WaitOne(); Console.WriteLine("Finishing thread MySync"); } } class Program { static void Main(string[] args) { AutoResetEvent myEvent = new AutoResetEvent(false); MySync mySync = new MySync(myEvent); ThreadPool.QueueUserWorkItem(mySync.ThreadMain); Console.WriteLine("Press enter to continue..."); Console.ReadLine(); myEvent.Set(); Console.WriteLine("Press enter to continue..."); Console.ReadLine(); Console.WriteLine("Finishing"); } } </code></pre> <p>Don't confuse this with a shared resource where the access order doesn't matter. For example, if you have a shared list or a shared dictionary you need to wrap it in a mutex in order to guarantee that they execute correctly.</p> <pre><code>// Mutex example object mySync = new object(); Dictionary<int, int> myDict = new Dictionary<int, int>(); void threadMainA() { lock(mySync) { mySync[foo] = bar; } } void threadMainB() { lock(mySync) { mySync[bar] = foo; } } </code></pre>

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