public ObservableCollection <RecipeGroup> UpdateListContents() { _expandedGroups = new ObservableCollection <RecipeGroup>(); foreach (var group in _allGroups) { var newGroup = new RecipeGroup(group.Title, group.ShortName, group.Expanded) { RecipeCount = group.Count }; if (group.Expanded) { foreach (var recipe in group) { newGroup.Add(recipe); } } _expandedGroups.Add(newGroup); } return(_expandedGroups); }