Check if the event is hooked with the Handler

EventHandlerFetcher.cs

        public static void Usage()
        {
            var instance = new Timer();

            // check if the event is assigned a handler
            if (GetEventHandler(instance, "Elapsed", "ElapsedEventHandler") == null)
            {
                throw new InvalidOperationException(string.Format("The Timer elapsed event must be assigned an event handler. Source: {0}", type.FullName));
            }    
        }

        /// <summary>
        /// Gets the event handler.
        /// </summary>
        /// <param name="classInstance">The class instance.</param>
        /// <param name="eventName">Name of the event.</param>
        /// <returns></returns>
        static ElapsedEventHandler GetEventHandler(Timer classInstance, string eventName, string eventHandler)
        {
            ElapsedEventHandler eventDelegate = null;
            Type classType = classInstance.GetType();
            var eventField = classType.GetFields(BindingFlags.NonPublic | BindingFlags.Instance);
            var handler = eventField.FirstOrDefault(x => (x.FieldType.Name == eventHandler));

            if (handler != null)
            {
                eventDelegate = (ElapsedEventHandler)handler.GetValue(classInstance);
            }

            return eventDelegate;
        }