使用PDFSharp将多个.rdlc报告渲染为单个PDF

我正在运行多个报告，并将它们组合成一个PDF文件。对于每个报告，我将数据源、参数和报告路径传递给以下对象。结果是一个具有正确页数的PDF文件，但所有页面都是空白的。我错过了什么？

LocalReport report = null;
PdfDocument pdfDoc = new PdfDocument();
private void ProcessReport(
    ReportDataSource reportDS, 
    ReportParameter[] reportParms, 
    string reportPath)
{
    string format = "PDF";
    string deviceInfo = null;
    string encoding = String.Empty;
    string mimeType = String.Empty;
    string extension = String.Empty;
    Warning[] warnings = null;
    string[] streamIDs = null;
    report = new LocalReport();
    report.EnableExternalImages = true;
    report.ReportPath = reportPath;
    if (reportParms != null)
        report.SetParameters(reportParms);
    if (reportDS != null)
        report.DataSources.Add(reportDS);
    Byte[] pdfArray = report.Render(
        format, 
        deviceInfo, 
        out mimeType, 
        out encoding,
        out extension, 
        out streamIDs, 
        out warnings);
    //Stream s = new MemoryStream(pdfArray);
    MemoryStream ms = new MemoryStream(pdfArray);
    PdfDocument tempPDFDoc = PdfReader.Open(ms, PdfDocumentOpenMode.Import);
    for (int i = 0; i < tempPDFDoc.PageCount; i++)
    {
        PdfPage page = tempPDFDoc.Pages[i];
        pdfDoc.AddPage(page);
    }
}