RDLC 子报表不出来的原因

做RDLC的子报表需要几个注意点
先贴一下源代码. 部分, 主要用来提供数据源.

    public interface IMakeReport {
        byte[] MakePdf(ReportDataModel reportModel, WReportTemplate tpl);
    }

    /// <summary>
    /// 报表创建工具
    /// </summary>
    public class MakeReport : IMakeReport
    {

        ReportDataModel reportModel;

        WReportTemplate tpl;

        public virtual byte[] MakePdf(ReportDataModel reportModel, WReportTemplate tpl)
        {
            this.reportModel = reportModel;
            this.tpl = tpl;

            var ReportTemplateFileDirectory = GConfig.GetConfigByCache("ReportTemplateFileDirectory") as string;

            LocalReport report = new LocalReport();
            //设置需要打印的报表的文件名称。

            report.EnableExternalImages = true;
            report.ShowDetailedSubreportMessages = true;


            report.ReportPath = ReportTemplateFileDirectory + tpl.MasterTplFileName;

            //创建要打印的数据源 
            ReportDataSource master = new ReportDataSource("Master", new List<ReportDataModel>() { reportModel });
            report.DataSources.Add(master);
            if (reportModel.Details != null)
            {
                ReportDataSource details = new ReportDataSource("Details", reportModel.Details);
                report.DataSources.Add(details);
            }
            if (reportModel.WSWDetails != null)
            {
                ReportDataSource wswdetails = new ReportDataSource("WSWDetails", reportModel.WSWDetails);
                report.DataSources.Add(wswdetails);
            }

            report.SubreportProcessing += Report_SubreportProcessing; 

            //刷新报表中的需要呈现的数据
            report.Refresh();


            Warning[] warnings;
            string[] streamids;

            string mimeType;
            string encoding;
            string extension;

            string outType = "PDF";//PDF,Word,Excel 都可以

            byte[] bytes = report.Render(outType,
                                        null,
                                        out mimeType,
                                        out encoding,
                                        out extension,
                                        out streamids,
                                        out warnings);

            return bytes;

            // 参考http://blog.csdn.net/Ealing/article/details/15814647
            // 将报表的内容输出为指定格式的数据流。
            //string deviceInfo =
            //  "<DeviceInfo>" +
            //  "  <OutputFormat>EMF</OutputFormat>" +
            //  "  <PageWidth>8.5in</PageWidth>" +
            //  "  <PageHeight>11in</PageHeight>" +
            //  "  <MarginTop>0.25in</MarginTop>" +
            //  "  <MarginLeft>0.25in</MarginLeft>" +
            //  "  <MarginRight>0.25in</MarginRight>" +
            //  "  <MarginBottom>0.25in</MarginBottom>" +
            //   "</DeviceInfo>";
            // Warning[] warnings;
            // //将报表的内容按照deviceInfo指定的格式输出到CreateStream函数提供的Stream中。
            // report.Render("Image", deviceInfo, CreateStream, out warnings);

            //下面是直接输出的代码
            //Response.Clear();
            //Response.Buffer = true;
            //Response.ContentType = mimeType;
            //Response.AddHeader("content-disposition", "attachment;filename=" + fileName + "." + extension);
            //Response.BinaryWrite(bytes);

            //Response.Flush(); 


            //ReportViewer1.Dispose();
            //ReportViewer1 = null; 
        }

        private void Report_SubreportProcessing(object sender, SubreportProcessingEventArgs e)
        {
            //这里是处理子报表的时候会执行的代码. 主要是提供数据源

            //这里是取得主报告传过来的参数.
            string ReportDetailId = e.Parameters["ReportDetailId"].Values[0];

            List<WDrugSensitivityTestReport> data = reportModel.ThreeDetails.Where(a => a.ReportDetailId == ReportDetailId).ToList();
            if (data==null)
            {
                data = new List<WDrugSensitivityTestReport>();
            }
            //这里的ThreeDetails 是子报表中的数据集名称
            ReportDataSource threeDetails = new ReportDataSource("ThreeDetails", 
                                                                    data.ToArray()
                                                                    );
            e.DataSources.Add(threeDetails); 
        }
    }

下面是RDLC模版文件的一些注意事项.