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

namespace JD.Core
{
    public class MultiThreadedObservableRangeCollection<T> : ObservableRangeCollection<T>
    {
        public override event NotifyCollectionChangedEventHandler CollectionChanged;
        protected override void OnCollectionChanged(NotifyCollectionChangedEventArgs e)
        {
            var CollectionChanged = this.CollectionChanged;
            if (CollectionChanged != null)
            {
                foreach (NotifyCollectionChangedEventHandler nh in CollectionChanged.GetInvocationList())
                {
                    var dispObj = nh.Target as DispatcherObject;
                    if (dispObj != null)
                    {
                        var dispatcher = dispObj.Dispatcher;
                        if (dispatcher != null && !dispatcher.CheckAccess())
                        {
                            dispatcher.BeginInvoke(
                                (Action)(() => nh.Invoke(this,
                                    new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset))),
                                DispatcherPriority.DataBind);
                            continue;
                        }
                    }
                    nh.Invoke(this, e);
                }
            }
        }
    }
}