﻿using System;
using System.Collections.ObjectModel;
using System.Collections.Specialized;
using System.Linq;
using System.Windows.Threading;

namespace DemosBrowser.Toolkit.Helper
{
    public class MTObservableCollection<T> : ObservableCollection<T>
    {
        public override event NotifyCollectionChangedEventHandler CollectionChanged;

        protected override void OnCollectionChanged(NotifyCollectionChangedEventArgs e)
        {
            using (BlockReentrancy())
            {
                var eh = CollectionChanged;
                if (eh == null) return;

                var dispatcher = (from NotifyCollectionChangedEventHandler nh in eh.GetInvocationList()
                                  let dpo = nh.Target as DispatcherObject
                                  where dpo != null
                                  select dpo.Dispatcher).FirstOrDefault();

                if (dispatcher != null && dispatcher.CheckAccess() == false)
                {
                    dispatcher.Invoke(DispatcherPriority.DataBind, (Action)(() => OnCollectionChanged(e)));
                }
                else
                {
                    foreach (NotifyCollectionChangedEventHandler nh in eh.GetInvocationList())
                        nh.Invoke(this, e);
                }
            }
        }
    }
}