public static void FilledByTail(this LinkedList<_DropdownlistLinkedNodeModel> models, Project tail) { while (tail.Parent != null) { _DropdownlistLinkedNodeModel nodeModel = new _DropdownlistLinkedNodeModel(); nodeModel.filledBy(tail); models.AddFirst(nodeModel); tail = tail.Parent; } _DropdownlistLinkedNodeModel firstNode = new _DropdownlistLinkedNodeModel { CurrentProject = new LiteItemModel() }; firstNode.CurrentProject.FilledBy(tail); models.AddFirst(firstNode); }