How can I send a file document to the printer and have it print?

Adding a new answer to this as the question of printing PDF’s in .net has been around for a long time and most of the answers pre-date the Google Pdfium library, which now has a .net wrapper. For me I was researching this problem myself and kept coming up blank, trying to do hacky solutions like spawning Acrobat or other PDF readers, or running into commercial libraries that are expensive and have not very compatible licensing terms. But the Google Pdfium library and the PdfiumViewer .net wrapper are Open Source so are a great solution for a lot of developers, myself included. PdfiumViewer is licensed under the Apache 2.0 license.

You can get the NuGet package here:

https://www.nuget.org/packages/PdfiumViewer/

and you can find the source code here:

https://github.com/pvginkel/PdfiumViewer

Here is some simple code that will silently print any number of copies of a PDF file from it’s filename. You can load PDF’s from a stream also (which is how we normally do it), and you can easily figure that out looking at the code or examples. There is also a WinForm PDF file view so you can also render the PDF files into a view or do print preview on them. For us I simply needed a way to silently print the PDF file to a specific printer on demand.

public bool PrintPDF(
    string printer,
    string paperName,
    string filename,
    int copies)
{
    try {
        // Create the printer settings for our printer
        var printerSettings = new PrinterSettings {
            PrinterName = printer,
            Copies = (short)copies,
        };

        // Create our page settings for the paper size selected
        var pageSettings = new PageSettings(printerSettings) {
            Margins = new Margins(0, 0, 0, 0),
        };
        foreach (PaperSize paperSize in printerSettings.PaperSizes) {
            if (paperSize.PaperName == paperName) {
                pageSettings.PaperSize = paperSize;
                break;
            }
        }

        // Now print the PDF document
        using (var document = PdfDocument.Load(filename)) {
            using (var printDocument = document.CreatePrintDocument()) {
                printDocument.PrinterSettings = printerSettings;
                printDocument.DefaultPageSettings = pageSettings;
                printDocument.PrintController = new StandardPrintController();
                printDocument.Print();
            }
        }
        return true;
    } catch {
        return false;
    }
}