How to access methods in a subclass of a class

I have a class file in my project:

class DataManager
{
public class LocalDB
{
public void CreateDatabase() { }
}
}

Now if I'm in my forms code and I have "DataManager DataManager = new DataManager();" present, why can I not call the CreateDatabase method in the LocalDB subclass. I can get as far as DataManager.LocalDB, but when I hit another period I only get "Equals" and "ReferenceEquals", but no "CreateDatabase".

Thanks!