SetHdevmode does not seem to be working

I am new to printing in C#.  I have put together code gathered from several places but am having lots of difficulties. I am trying to use the PdfiumViewer to print PDFs without user intervention.  I have managed to save printer setting in bin files and have been able to verify that what is in the bin file is correct.  However when I try to set the printer setting using the bin files the printer is not using the settings.  Below is the code can someone please tell me what I maybe doing wrong?

                 //pdf path and file name
                 var path = txtPDF.Text;

                 
                //load PdfiumViewer with document
                using (var document = PdfDocument.Load(path))
                    {

                    //CREATE print document using PdfiumViewer
                    using (var printDocument = document.CreatePrintDocument())
                        {

                            //copy bin file into array
                            byte[] bytearray = File.ReadAllBytes(NameAndPathOfBinFile);

                            //create pointer to where the "array holding the bin file" will be stored
                            var pDevMode = Marshal.AllocHGlobal(bytearray.Length);

                            //copy "bin file array" to pointer location
                            Marshal.Copy(bytearray, 0, pDevMode, bytearray.Length);

                        //set point the iPdfiumViewer devmode pointer of loaded "bin file array"
                        printDocument.PrinterSettings.SetHdevmode(pDevMode);

                        //get set printer name
                        printDocument.PrinterSettings.PrinterName = printerName;


                        //This just shows the dialog box to so I can verify the settings and I have verified that the setting are correct
                        int value = AdvancedDocumentProperties(IntPtr.Zero, IntPtr.Zero, printerName, pDevMode, pDevMode);

                        //print the document
                        printDocument.Print();



                        }
                    }
                }