C#获得打印句柄

            PrintDocument pdc = new PrintDocument();
            string printerName = pdc.PrinterSettings.PrinterName;
            IntPtr pPrinter = IntPtr.Zero;
            IntPtr nullPointer = IntPtr.Zero;
            if (printerName != null && printerName.Length > 0)
            {

                OpenPrinter(printerName, ref pPrinter, ref nullPointer);
            }