@Monsieur OUXX, File.GetFolder may be a useful addition, but that's rather not a "missing property" in the sense this thread was created for.
Regarding AudioChannel.PreferredType - frankly I'd rather suggest redesigning of how channels work, because now it looks like you are trying to find a way to "hack the system".
Regarding AudioChannel.PreferredType - frankly I'd rather suggest redesigning of how channels work, because now it looks like you are trying to find a way to "hack the system".