MVVM: новый взгляд

[DataContract]
public class SaveViewModel : ViewModel
{
    public SaveViewModel()
    {
        Initialize();
    }
      
    public bool DialogResult { get; set; }
    public ObservableCollection<DocumentView> Items { get; private set; }
    public ObservableCollection<DocumentView> SelectedItems { get; private set; }      
    public bool IsAllItemsSelected
    {
        get
        {
            return Items.Where(i => ApplicationCommands.Save.CanExecute(null, i)).
            	All(i => SelectedItems.Contains(i));
        }
    }
    
    public void SetItems(
    	ObservableCollection<DocumentView> items, 
    	IEnumerable<DocumentView> selectedItems)
    {
        Items = items;
        RaisePropertyChanged(() => Items);
        SelectedItems.Clear();
        if (selectedItems != null)
            SelectedItems.AddRange(selectedItems);
    }
      
    [OnDeserialized]
    private void Initialize(StreamingContext context = default(StreamingContext))
    {
        Executed();
        CanExecute();
        SelectedItems = new ObservableCollection<DocumentView>();
        SelectedItems.CollectionChanged += (sender, args) => 
        	RaisePropertyChanged(() => IsAllItemsSelected);
    }
      
    private void CanExecute()
    {
        this[ApplicationCommands.Save].CanExecute += (sender, args) => 
            args.CanExecute = SelectedItems.Any(i => 
            	ApplicationCommands.Save.CanExecute(null, i));
    }
      
    private void Executed()
    {
        this[ApplicationCommands.Save].Executed += (sender, args) =>
        {
            var cancelArgs = new CancelEventArgs();
            foreach (var item in SelectedItems.
            	Where(item => ApplicationCommands.Save.CanExecute(null, item)))
            {
                ApplicationCommands.Save.Execute(cancelArgs, item);
                if (cancelArgs.Cancel) break;
            }
              
            if (SelectedItems.Any(i => 
            	ApplicationCommands.Save.CanExecute(null, i)))
            {
                DialogResult = true;
                return;
            }
              
            DialogResult = true;
            OnClosing(sender, new CancelEventArgs());
        };
          
        this[ApplicationCommands.Close].Executed += (sender, args) =>
        {
            DialogResult = args.Parameter == null;
            OnClosing(sender, new CancelEventArgs());
        };
          
        this[ApplicationCommands.SelectAll].Executed += (sender, args) =>
        {
            var isChecked = (bool) args.Parameter;
            foreach (var item in Items)
            {
                if (!SelectedItems.Contains(item) && isChecked) 
                	SelectedItems.Add(item);
                if (SelectedItems.Contains(item) && !isChecked) 
                	SelectedItems.Remove(item);
            }
        };
    }
}