// SumatraPDF.exe -print-to-default -silent "file.pdf" -print-to <printer-name>

Process.Start(new ProcessStartInfo
{
    FileName = "SumatraPDF.exe",
    Arguments = $"-print-to-default -silent \"{pdfFilePath}\" -print-to \"{printerName}\"",
    CreateNoWindow = true,
    UseShellExecute = false
});

// PDFtoPrinter filename.pdf "Name of Printer"

Process.Start(new ProcessStartInfo
{
    FileName = "PDFtoPrinter.exe",
    Arguments = $"\"{pdfFilePath}\" \"{printerName}\"",
    CreateNoWindow = true,
    UseShellExecute = false
});

// using DevExpress.Pdf;
using (var stream = new MemoryStream(result.PDF))
{
	using (var documentProcessor = new PdfDocumentProcessor())
	{
		documentProcessor.LoadDocument(stream, false);
		var pageNumbers = documentProcessor.Document.Pages.Select(x => x.GetPageIndex() + 1).ToArray();

		var printerSettings = new PrinterSettings
		{
			PrinterName = printerName
		};

		var pdfPrinterSettings = new PdfPrinterSettings(printerSettings)
		{
			PageNumbers = pageNumbers
		};

		documentProcessor.Print(pdfPrinterSettings);
	}
}