What is the thread-safe way to fire an event?

30.

if(myEvent != null)
    lock (myEvent)
    myEvent(sender, e);

if(myEvent != null)
    myEvent(sender, e);

EventHandler temp = myEvent;
    if(temp != null)
    temp(sender, e);

if(myEvent!=null)
    Monitor.PulseAll (myEvent)

View Description

Normally we fire event this way: if(myEvent!=null) myEvent(sender, e); But in multi-threaded environment there is a possibility that a client oversubscribes from the event after we passed the check myEvent!=null. To avoid the race condition we can store the event to temporary variable and then work with it. Copying of delegates is an atomic operation in terms of multi-threading.