Call DAL Method from UI Layer

public class TutorRegistratonDAL
{
        SqlConnection con = new SqlConnection();
        SqlTransaction tr = new SqlTransaction();
        
        public DataSet Inserttutor(DataSet ds_sub,DataSet ds_lang,DataSet ds_time)
        {
            con.ConnectionString = StrCon;

            try
            {
                con.Open();
                SqlBulkCopy sub_copy = new SqlBulkCopy(con);
                sub_copy.DestinationTableName = "tutor_subjects";
                DataTable sub_dt = new DataTable();
                sub_dt= ds_sub.Tables[0];
                sub_copy.WriteToServer(sub_dt);
                SqlBulkCopy lang_copy = new SqlBulkCopy(con);
                lang_copy.DestinationTableName = "tutor_languages";
                DataTable lang_dt = new DataTable();
                lang_dt = ds_lang.Tables[0];
                lang_copy.WriteToServer(lang_dt);
                tr.Commit();
                return true;
            }
            catch (Exception ex)
            {
                tr.Rollback();
                return false;
            }
            finally
            {            
                con.Close();
            }
         }