Linq 自定义SQL语句返回数值

               string sql = "SELECT count(char_KCJLB_SN) FROM tbKuCunJiLuBiao";
                sqlcon.Open();
                SQLServerDBDataContext conn = new SQLServerDBDataContext(sqlcon);
                IEnumerable<int> ie_kc = conn.ExecuteQuery<int>(sql);
                IList<int> a = new List<int>();

                foreach (var t in ie_kc)
                {
                    a.Add(t);
                }
                sqlcon.Close();
                return a.First<int>();