Triggering "CanExecute" on postsharp [Command] when a document changes?

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I am currently migrating a project to PostSharp to remove a lot of boilerplate code, most of it is going very smoothly but I'm left confused about how to force a command to recheck if it CanExecute. I expected PostSharp would inspect the command like it does properties to check for dependencies, here is a minimalist sample

[NotifyPropertyChanged]
public class MyWindowViewModel
{
    /// Anything bound to this refreshes just fine as expected
    public ObservableCollection<SomeType> Documents = new ObservableCollection<SomeType>();

   [Command]
   public ICommand AddDocumentCommand { get; set; }
   public void ExecuteAddDocument () { Documents.Add(new SomeType()); }

   [Command]
   public ICommand CloseDocumentCommand { get; set; }
   public bool CanExecuteCloseDocument () => Documents.Any(); 
   public void ExecuteCloseDocument () { Documents.Remove(Documents.Last()); }        
}

At start the collection is empty and the button attached to the close command is greyed as expected, however adding a document through the button attached to AddDocument doesn't activate the close document button, what is the appropriate way to accomplish what I need? Is PostSharp only considering assignments and not method calls as changes or is it something else entirely?

postsharp wpf .net c#
2 Answers

With PostSharp LINQ expression (or virtual calls, delegates, external methods) wouldn't work well for CanExecute's.

But expression on properties that implement INotifyPropertyChanged work fantastic (even for nested properties). ObservableCollection implements INotifyPropertyChanged, we don't need LINQ:

public bool CanExecuteCloseDocument => Documents.Count > 0;

user_7807410
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