nature_net.configurations.get_or_create_collection C# (CSharp) Метод

        public static int get_or_create_collection(int user_id, int activity_id, DateTime dt)
        {
            naturenet_dataclassDataContext db = new naturenet_dataclassDataContext();
            var r = from c in db.Collections
                    where ((c.user_id == user_id) && c.activity_id == activity_id)
                    orderby c.date descending
                    select c;
            if (r.Count() != 0)
            {
                foreach (Collection col in r)
                {
                    if (configurations.GetDate_Formatted(col.date) == configurations.GetDate_Formatted(dt))
                        return col.id;
                }
            }

            // create new collection
            Collection cl = new Collection();
            cl.activity_id = activity_id;
            cl.date = dt;
            cl.name = configurations.GetDate_Formatted(dt);
            cl.user_id = user_id;
            database_manager.InsertCollection(cl);
            return cl.id;
        }