protected override void OnBindingContextChanged()
            {
                base.OnBindingContextChanged();

                if (_itemTemplateNode == null && PresentedView != null)
                {
                    _itemTemplateNode = new ItemTemplateNode(this);
                    _collectionView.AddLayoutChild(_itemTemplateNode);
                }
            }
 private void AddLayoutChild(ItemTemplateNode childNode)
 {
     _layoutChildren.Add(childNode);
     Invalidate();
 }