ChangeNotifier.cs

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using System;

public static class ChangeNotifier
{
    private static Dictionary<Type, List<WeakReference>> listeners = new Dictionary<Type, List<WeakReference>>();
    private static List<WeakReference> checkersToRemove = new List<WeakReference>();

    public static void Notify(Type tableType)
    {
        if (listeners.ContainsKey(tableType))
        {
            checkersToRemove.Clear();
            var listenersOfType = listeners[tableType];
            for (int i = 0; i < listenersOfType.Count; i++)
            {
                var weak = listenersOfType[i];
                ChangeChecker cc = (ChangeChecker)weak.Target;
                if (cc == null || !weak.IsAlive)
                {
                    checkersToRemove.Add(weak);
                }
                else
                {
                    cc.IsUpdated = true;
                }
            }

            foreach (var checkerToRemove in checkersToRemove)
                listenersOfType.Remove(checkerToRemove);
        }
    }

    public static void AddListener(ChangeChecker checker, Type tableType)
    {
        WeakReference wr = new WeakReference(checker);
        if (listeners.ContainsKey(tableType))
            listeners[tableType].Add(wr);
        else
        {
            List<WeakReference> changings = new List<WeakReference> { wr };
            listeners.Add(tableType, changings);
        }
    }

    public static void AddListener(ChangeChecker checker, params Type[] tableTypes)
    {
        foreach (Type tableType in tableTypes)
        {
            AddListener(checker, tableType);
        }
    }
}