通过Demo来细看C#事件的内在机制

public delegate void ProcessEventHandler(string name);
    public class CharlesLog
    {
       public event ProcessEventHandler processEvent;
       public void ProcessHandler(string name)
       {
           if (processEvent != null)
           {
               processEvent(name);
           }
           else
           {
               processEvent = new ProcessEventHandler(DefaultHandler);
               processEvent(name);
           }
       }
        public void DefaultHandler(string name)
        {
            Console.WriteLine("default Process!");
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            CharlesLog charlesLog = new CharlesLog();
            charlesLog.processEvent += new ProcessEventHandler(CustomProcess); 
            charlesLog.ProcessHandler("CharlesChen");
        }
        public static void CustomProcess(string name)
        {
            Console.WriteLine("custom Process!");
        }
}