Pass (Send) dynamic list to static list in Linq in ASP.Net

How to pass dynamic list to static list.

1. This return list

        public List<Category> Category_All()
        {
            List<Category> AllCat = new List<Category>();

            string constr = ConfigurationManager.ConnectionStrings["mysql"].ConnectionString;
            using (MySqlConnection con = new MySqlConnection(constr))
            {
                string query = "SELECT zutry_term_taxonomy.term_id as categoryid, zutry_terms.name as categoryname, zutry_terms.slug as url, zutry_term_taxonomy.parent as parentid FROM zutry_terms LEFT JOIN zutry_term_taxonomy ON zutry_terms.term_id = zutry_term_taxonomy.term_id WHERE zutry_term_taxonomy.taxonomy = 'product_cat'";
                using (MySqlCommand cmd = new MySqlCommand(query))
                {
                    cmd.Connection = con;
                    con.Open();
                    using (MySqlDataReader sdr = cmd.ExecuteReader())
                    {
                        while (sdr.Read())
                        {
                            AllCat.Add(new Category
                            {
                                category_id = int.Parse(sdr["categoryid"].ToString()),
                                category_name = sdr["categoryname"].ToString(),
                                urlpath = sdr["url"].ToString(),
                                parentid = int.Parse(sdr["parentid"].ToString())
                                //banner = sdr["image"].ToString()
                            });
                        }
                    }
                    con.Close();
                }
            }

            return AllCat.ToList();
        }

2. Model of above

        public class Category
        {
            public int category_id { get; set; }
            public string category_name { get; set; }

            public string banner { get; set; }
            public string urlpath { get; set; }

            public int productid { get; set; }

            public int parentid { get; set; }
        }

            /// this is staic list which pass in below method,   intead of this static list i want to pass No 1 Method return list in Var generes
            var genres = new[] 
            {
                
               
                new Genre {Id = 1, Name = "Test Genre 1", ParentId = null},
                new Genre {Id = 2, Name = "Test Genre 2", ParentId = null},
                new Genre {Id = 3, Name = "Test Genre 3", ParentId = 1},
                new Genre {Id = 4, Name = "Test Genre 4", ParentId = 2},
                new Genre {Id = 5, Name = "Test Genre 5", ParentId = 3}
            };
           

            var result = genres.Select(g => SelectGenreName(genres, g));

        ///Method which take Ienumerable
        private static string SelectGenreName(IEnumerable<Genre> all, Genre g)
        {
            var s = g.Name + '/';
            if (g.ParentId.HasValue)
            {
                s = SelectGenreName(all, all.Single(x => x.Id == g.ParentId.Value));
            }
            return s;
        }