set the printer name using C# . Also avoid the popup dialogue box.

ReportDocument rptH = new ReportDocument()
  string PrinterName = "Printronix P8000";
                            PrinterSettings objPrintSettings = new PrinterSettings();
                            if (!string.IsNullOrEmpty(PrinterName))
                            rptH.PrintOptions.PrinterName = PrinterName;
                            rptH.PrintToPrinter(1, true, 0, 0);