Following code prints names of classes in specified namespace defined in current assembly.
As other guys pointed out, a namespace can be scattered between different modules, so you need to get a list of assemblies first.
string @namespacenspace = "..."; var q = from t in Assembly.GetExecutingAssembly().GetTypes() where t.IsClass && t.Namespace == @namespacenspace select t; q.ToList().ForEach(t => Console.WriteLine(t.Name));