Generally accepted way to avoid KnownType attribute for every derived class

Question

Is there a generally accepted way to avoid having to use KnownType attributes on WCF services? I\'ve been doing some research, and it looks like there are two options:

Answer 1

Here's my variant on the accepted answer:

    private static IEnumerable GetKnownTypes() {
        Type baseType = typeof(MyBaseType);
        return AppDomain.CurrentDomain.GetAssemblies()
            .SelectMany(x => x.DefinedTypes)
            .Where(x => x.IsClass && !x.IsAbstract && x.GetCustomAttribute() != null && baseType.IsAssignableFrom(x));
    }

The differences are:

1. Looks at all loaded assemblies.
2. Checks some bits we are interested in (DataContract I think is required if you're using DataContractJsonSerializer) such as being a concrete class.
3. You can use isSubclassOf here, I tend to prefer IsAssignableFrom in general to catch all overridden variants. In particular I think it works with generics.
4. Take advantage of KnownTypes accepting an IEnumerable (if it matters in this case, probably not) instead of converting to an array.