public class WeakList<T>
        where T : class
    {
        List<WeakReference> _weakList = new List<WeakReference>();

        public void Add(T value)
        {
            _weakList.Add(new WeakReference(value));
        }

        public void Remove(T value)
        {
            for (int i = _weakList.Count - 1; i >= 0; i--)
            {
                var item = (T)_weakList[i].Target;
                if (item == null || EqualityComparer<T>.Default.Equals(item, value))
                    _weakList.RemoveAt(i);
            }
        }

        public T[] Items
        {
            get
            {
                var result = new List<T>(_weakList.Count);
                for (int i = _weakList.Count - 1; i >= 0; i--)
                {
                    var item = (T)_weakList[i].Target;
                    if (item != null)
                        result.Add(item);
                    else
                        _weakList.RemoveAt(i);
                }
                result.Reverse();
                return result.ToArray();
            }
        }
    }

    public class WeakEventHandler : WeakList<EventHandler>
    {
        public void Invoke(object sender, EventArgs e)
        {
            foreach (var handler in Items)
                handler(sender, e);
        }
    }

    public class WeakAction : WeakList<Action>
    {
        public void Invoke()
        {
            foreach (var handler in Items)
                handler();
        }
    }