csharp_eventdelegates

gistfile1.txt

using System;
using System.Collections.Generic;
using System.Linq;
class Program
{
    public delegate void MessageArrivedHandler(string message);

    class Publisher
    {
        private event MessageArrivedHandler _messageArrived = delegate  {};
        public event MessageArrivedHandler MessageArrived {
            add {
                _messageArrived += value;
            }
            remove {
                _messageArrived -= value;
            }
        }

        public void RaiseEvent(string message)
        {
            // So instead of 'Invoke', you can use 'GetInvocationList' and wrap each invocation with try-catch
            // _messageArrived?.Invoke(message);

            Delegate[] handlers = _messageArrived.GetInvocationList();
            foreach (Delegate handler in handlers)
            {
                try
                {
                    handler.DynamicInvoke(message);
                }
                catch (Exception ex)
                {
                    Console.WriteLine($"An error occurred: {ex.Message}");
                }
            }
        }
    }

    record Subscriber(string Name)
    {
        public string SubscriberName { get; set; } = Name;
        public void Subscribe(Publisher pub)
        {
            pub.MessageArrived += HandleEvent;
        }

        public void HandleEvent(string message)
        {
            Console.WriteLine($"Event handled by subscriber '{SubscriberName}': {message}");
        }
    }

    static void Main(string[] args)
    {
        Publisher pub = new Publisher();
        Subscriber sub1 = new Subscriber("sub1");
        Subscriber sub2 = new Subscriber("sub2");
        sub1.Subscribe(pub);
        sub2.Subscribe(pub);
        pub.RaiseEvent("Hello world."); 

        Console.WriteLine("Done!");
    }
}