private void renderButton_Click(object sender, EventArgs e)
        {
            Warning[] warnings;
            string[] streamids;
            string mimeType;
            string encoding;
            string filenameExtension;

            //Render the report to a byte array
            byte[] bytes;
            if (reportViewer1.ProcessingMode == ProcessingMode.Local)
            {
                bytes = reportViewer1.LocalReport.Render("PDF", null, out mimeType,
                out encoding, out filenameExtension, out streamids, out warnings);
            }
            else
            {
                bytes = reportViewer1.ServerReport.Render("PDF", null, out mimeType,
             out encoding, out filenameExtension, out streamids, out warnings);
            }

            //Write report out to temporary PDF file
            reportFilename = Path.Combine(Path.GetTempPath(), "Report.pdf");
            using (FileStream fs = new FileStream(reportFilename, FileMode.Create))
            {
                fs.Write(bytes, 0, bytes.Length);
            }
        }