c#多表关联打印问题

有一个主表receive_main，一个从表receive_details，从表是主表的明细，想把主表及从表下面的明细列印出来，但总是没有数据显示，明明数据集里面已经有数据！数据集填充语句如下：
select receive_main.sn,receive_main.cdate,receive_main.department,receive_main.lister,receive_main.deliverdate,receive_main.po,receive_main.pno,receive_main.receiveman,receive_main.customer,receive_details.name,receive_details.spec,receive_details.cinvaddcode,receive_details.cinvcode,receive_details.unit,receive_details.renumber from receive_main left join receive_details on receive_main.sn=receive_details.sn where receive_main.sn=71656
请问碰到这种多表关联的如何填充！到底还是其他地方出问题了，