初识三层架构(3)

                    return cmd.ExecuteScalar();
                }
            }
        }
        public static DataTable ExecuteDataTable(string sql, params SqlParameter[] parameters)
        {
            using (SqlConnection con = new SqlConnection(conStr))
            {
                con.Open();
                using (SqlCommand cmd = con.CreateCommand())
                {
                    cmd.CommandText = sql;
                    if (parameters != null)
                    {
                        foreach (SqlParameter param in parameters)
                        {
                            cmd.Parameters.Add(param);
                        }
                    }
                    DataTable dt = new DataTable();
                    SqlDataAdapter da = new SqlDataAdapter(cmd);
                    da.Fill(dt);
                    return dt;
                }
            }