/// <summary>
/// Add descendents to this instance and all ancestor instances.
/// </summary>
/// <param name="items"></param>
/// <param name="depth"></param>
private void AddDescendants(IEnumerable <ImageItem> items, int depth)
{
DescendantImages.AddRange(items.Select(p => new DescendantImageItem()
{
Item = p, Depth = depth
}));
if (Parent != null)
{
Parent.AddDescendants(items, depth + 1);
}
}