/blog/code/2012/03/16/telerik-reporting--export-on-button-click

TelerikReportingExportToPdf.cs

void ExportToPDF(Telerik.Reporting.Report reportToExport)
    {
        ReportProcessor reportProcessor = new ReportProcessor();
        RenderingResult result = reportProcessor.RenderReport("PDF", reportToExport, null);
  
        string fileName = result.DocumentName + ".pdf";
  
        Response.Clear();
        Response.ContentType = result.MimeType;
        Response.Cache.SetCacheability(HttpCacheability.Private);
        Response.Expires = -1;
        Response.Buffer = true;
  
        Response.AddHeader("Content-Disposition",
                           string.Format("{0};FileName=\"{1}\"",
                                         "attachment",
                                         fileName));
  
        Response.BinaryWrite(result.DocumentBytes);
        Response.End();
    }