public MainViewModel()
{
HierarchicalElements = new ObservableCollection <HierarchicalElementViewModel>();
ListElements = new ObservableCollection <ListElementViewModel>();
AddHierarchicalElementCommand = new RelayCommand(AddHierarchicalElement);
RemoveHierarchicalElementCommand = new RelayCommand(
RemoveHierarchicalElement,
() => Manager.SelectedElement is HierarchicalElementViewModel);
AddListElementCommand = new RelayCommand(AddListElement);
RemoveListElementCommand = new RelayCommand(
RemoveListElement,
() => Manager.SelectedElement is ListElementViewModel);
Manager = new SelectionManager.SelectionManager();
Manager.PropertyChanged += ManagerOnPropertyChanged;
Manager.AddCollection(HierarchicalElements);
Manager.AddCollection(ListElements);
}
