viewer.LocalReport.SubreportProcessing += new SubreportProcessingEventHandler(LocalReport_SubreportProcessing);
//主函数添加
 void LocalReport_SubreportProcessing(object sender, Microsoft.Reporting.WebForms.SubreportProcessingEventArgs e)
        {
            var errCode = 100;
            try
            {
                if (e.DataSourceNames[0] == "dsJcxh")
                          //这里引号里替换成子报表的数据集名称
                {
                    errCode = 3;
                    e.DataSources.Add(new ReportDataSource("dsJcxh", GetSupervisionSamplingDetailData(e)));
//如果只有1个子报表ELSE后面就不需要了，3个以上 多次IF判断就可以了
                }
                else
                {
                    errCode = 4;
                    e.DataSources.Add(new ReportDataSource("dsUr", GetUseRegisterData(e)));
                }
            }
            catch (Exception ex)
            {
                Response.Write(ex.Message + ":" + errCode);
            }
        }
   public List<StatisticalLedger> GetSupervisionSamplingDetailData(SubreportProcessingEventArgs e) {
           //接受子报表RDLC里面的参数
            string productDictId =e.Parameters["productDictId"].Values[0];
            string spec = e.Parameters["spec"].Values[0];
            string certificateNo = e.Parameters["certificateNo"].Values[0];    
                   var list = new StatisticalLedgerBL().GetSupervisionSamplingDetailData(productDictId, spec, certificateNo);
            return list;
        }
        public List<StatisticalLedger1> GetUseRegisterData(SubreportProcessingEventArgs e)
        {
           //接受子报表RDLC里面的参数
            string productDictId = e.Parameters["productDictId"].Values[0];
            string spec = e.Parameters["spec"].Values[0];
            var list = new StatisticalLedgerBL().GetUseRegisterData(productDictId, spec);
            return list;
        }