EventHandler

        static void Main(string[] args)
        {
            //WorkPerformedHandler del1 = new WorkPerformedHandler(WorkPerformed1);
            //WorkPerformedHandler del2 = new WorkPerformedHandler(WorkPerformed2);
            //WorkPerformedHandler del3 = new WorkPerformedHandler(WorkPerformed3);

            //del1 += del2 + del3;

            //int finalHours = del1(10, WorkType.GenerateReports);
            //Console.WriteLine(finalHours);

            var worker = new Worker();
            worker.WorkPerformed += delegate(object sender, WorkPerformedEventArgs e)
            {
                Console.WriteLine("Hours worked: " + e.Hours + " " + e.WorkType);
            };
            worker.WorkCompleted += delegate(object sender, EventArgs e)
            {
                Console.WriteLine("Worker is done");
            };
            worker.DoWork(8, WorkType.GenerateReports);

            Console.Read();
}


    public enum WorkType
    {
        GoToMeetings,
        Golf,
        GenerateReports
    }

 public class Worker
    {
        public event EventHandler<WorkPerformedEventArgs> WorkPerformed;
        public event EventHandler WorkCompleted;

        public void DoWork(int hours, WorkType workType)
        {
            for (int i = 0; i < hours; i++)
            {
                System.Threading.Thread.Sleep(1000);
                OnWorkPerformed(i + 1, workType);
            }
            OnWorkCompleted();
        }

        protected virtual void OnWorkPerformed(int hours, WorkType workType)
        {
            //if (WorkPerformed != null)
            //{
            //    WorkPerformed(hours, workType);
            //}

            var del = WorkPerformed as EventHandler<WorkPerformedEventArgs>;
            if (del != null)
            {
                del(this, new WorkPerformedEventArgs(hours, workType));
            }
        }

        protected virtual void OnWorkCompleted()
        {
            //if (WorkCompleted != null)
            //{
            //    WorkCompleted(this, EventArgs.Empty);
            //}

            var del = WorkCompleted as EventHandler;
            if (del != null)
            {
                del(this, EventArgs.Empty);
            }
        }
    }