Allow Custom Collection Editor Declined - Not Valid

PropertyGrid allows assigning a custom editor based on property name, property type, or editor attribute. Property name requires listing all property names where the editor applies, editor attribute requires modifying the model which may not be accessible, and property type in XAML doesn't support generic types particularly well.

The built-in collection editor is assigned based on a typeof(IEnumerable).IsAssignableFrom().

A minimal solution (not supporting generic types) would be to allow assignment of a custom editor based on an interface implemented by the type. PropertyGrid.SetEditor(...) would enumerate all interfaces on a type and examine CustomEditorCollection[] for the interface. This would, among other things, allow assigning a custom editor for IEnumerable.

The goal is to have the custom collection editor assignment propagate down a hierarchy of nested collections like the built-in collection editor supports.

An alternative would be the ability to replace the built-in editors or perhaps exposing more members of PropertyGrid to make it easier to sub-class.