使用Windows窗体的PrintDocument将WPF FlowDocument直接保存为PDF文件

Question

I use Microsoft Visual Studio 2017 and Microsoft Print to PDF in Windows 10.

I try to make a PDF file of FlowDocument without PrintDialog and I know it's impossible in pure WPF. So I referred system.drawing.printing.PrintDocument of Windows Forms into my WPF project.

I'm stuck on the point of converting FlowDocument to PrintDocument.

PrintDocument _PrintDocument = (PrintDocument)FlowDocument1;

IDocumentPaginatorSource _DocumentPaginatorSource = FlowDocument1;
PrintDocument _PrintDocument = FlowDocument1;

Neither of them works.

Is it possible or is there any sideway to make PDF by assigning the folder and file name with code? Should I surely use 3rd party component?

Answer 1

If you can set the default printer to be the PDF or XPS then you can use this code snippet. It will use the default printer and then print the visual that you want. Bear in mind if you need different orientation than Landscape you should change it.
EDIT:
For completeness you can search for a printer queue that is PDF printing like this:

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Printing;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Media;
using System.Windows.Xps;
using System.Windows.Xps.Packaging;

namespace Services.Printing
{
    public static class PrintingService
    {
        public static void Print(Visual elementToPrint, string description)
        {
            using (var printServer = new LocalPrintServer())
            {
                var dialog = new PrintDialog();
                //Find the PDF printer
                var qs = printServer.GetPrintQueues();
                var queue = qs.FirstOrDefault(q => q.Name.Contains("PDF"));
                if(queue == null) {/*handle what you want to do here (possibly use XPS?)*/}
                dialog.PrintTicket.PageOrientation = PageOrientation.Landscape;
                dialog.PrintQueue = queue;
                dialog.PrintVisual(elementToPrint, description);
            }
        }
    }
}

Answer 2

It seems that there is no direct PDF file saving way without any dialog box under current Windows and WPF versions. But I got to the answer through PdfSharp.Xps. It is quite simple and the quility of documents is well preserved.

You can easily use it by Nuget Package Manager of Visual Studio.