DataTable.select() 返回 DataTable

        /**/
        /// <summary>
        /// 执行DataTable中的查询返回新的DataTable
        /// </summary>
        /// <param name="dt">源数据DataTable</param>
        /// <param name="condition">查询条件</param>
        /// <returns></returns>
        public DataTable GetNewDataTable(DataTable dt, string condition)
        {
            DataTable newdt = new DataTable();
            newdt = dt.Clone();
            DataRow[] dr = dt.Select(condition);
            for (int i = 0; i < dr.Length; i++)
            {
                newdt.ImportRow((DataRow)dr[i]);
            }
            return newdt;//返回的查询结果
        }