public void OpenNewPage <T>() where T : ViewModelBase
        {
            // TODO: USE DI
            var viewModel = (T)Activator.CreateInstance(typeof(T), _navigationUtility);

            CurrentViewModel = viewModel;
            CurrentViewModels.Add(CurrentViewModel);
            CurrentViewModelIndex = CurrentViewModels.IndexOf(CurrentViewModel);
        }
        private void NavigationClose(ViewModelBase viewModel)
        {
            var currentViewModel = CurrentViewModels.FirstOrDefault(item => item == viewModel);

            CurrentViewModels.Remove(currentViewModel);
        }
 private void OnCloseCurrentViewModel()
 {
     CurrentViewModels.RemoveAt(CurrentViewModelIndex);
 }