public L4S03() { InitializeComponent(); var shop = new Category { Name = "Продукты", Content = new ArrayList { new Category { Name="Овощи", Content=new ArrayList { new Ware { Name="Картофель", Quantity=100}, new Ware { Name="Морковь", Quantity=150, Content = new ArrayList{ new Category { Content=null, Name="Test"}}} } }, new Category { Name="Фрукты", Content=new ArrayList { new Ware { Name="Бананы", Quantity=50 }, new Ware { Name="Морковь", Quantity=70 } } } } }; tree.ItemsSource = new object[] { shop }; }