与另一个文档合并时从 PDFsharp 页面合并中删除页码

Question

I used PDFsharp to merge 2 PDF files. My code adds page numbering to the bottom of each page. Now I need to merge the created document with another PDF the same way. The issue I get is the page numbers on the part created from the last document are fine. The document created from the first merge has the new page number added over the top of the first set so there are now two page numbers on top of each other in the first set of pages. So in one spot I have both of these "Page 1 of 40" and Page "1 of 110" on top of each other.

Here is the code I used to merge the PDFs

using PdfSharp.Drawing;
using PdfSharp.Pdf;
using PdfSharp.Pdf.IO;

namespace SomeProject.Helpers
{
    public static class PDFHelper
    {
        public static void MergePDFFiles(string[] pdfFiles, string outputFilePath)
        {
            PdfDocument document = new PdfDocument();
            foreach (string pdfFile in pdfFiles)
            {
                PdfDocument inputPDFDocument = PdfReader.Open(pdfFile, PdfDocumentOpenMode.Import);
                document.Version = inputPDFDocument.Version;
                foreach (PdfPage page in inputPDFDocument.Pages)
                {
                    document.AddPage(page);
                }
            }

            // Set font for paging  
            XFont font = new XFont("Verdana", 9);
            XBrush brush = XBrushes.Black;
            // Create variable that store page count  
            string noPages = document.Pages.Count.ToString();
            // Set for loop of document page count and set page number using DrawString function of PdfSharp  
            for (int i = 0; i < document.Pages.Count; ++i)
            {
                PdfPage page = document.Pages[i];
                // Make a layout rectangle.  
                XRect layoutRectangle = new XRect(240 /*X*/ , page.Height - font.Height - 10 /*Y*/ , page.Width /*Width*/ , font.Height /*Height*/ );
                using (XGraphics gfx = XGraphics.FromPdfPage(page))
                {
                    gfx.DrawString("Page " + (i + 1).ToString() + " of " + noPages, font, brush, layoutRectangle, XStringFormats.Center);
                }
            }

            document.Save(outputFilePath);
        }
    }
}

Answer 1

A clean solution: only add the page numbers to the final documents. Keep copies of intermediate files without page numbers or create the files twice as needed.

A hack: draw a white rectangle below the new page numbers to hide anything that is already in that area. The PDF will have both page numbers, but only the most recent and current page number will be visible.

Removing page numbers is a bit complicated.