protected override void OnCollectionRemove(object sender, NotifyCollectionChangedEventArgs args)
        {
            var index = args.NewStartingIndex;
            int count = 1;

            if (args.OldItems != null)
            {
                count = args.OldItems.Count;
            }

            // Debug.LogFormat ("OnCollectionRepalce(index={0},count={1},datalen={2},items.count={3}) ", index, count,m_LoopVerticalScrollRect.dataLength,items.Count);
            if (index >= 0)
            {
                m_LoopVerticalScrollRect.RemoveAt(index, count);
            }
            else
            {
                m_LoopVerticalScrollRect.RemoveAt(0, count);
            }
        }