Add MigraDoc Table of Contents to PDFsharp PDF

Question

I am trying to use PDFsharp and MigraDoc to create a PDF report file from many other files.

Basically the workflow is as follows:

1. The user uploads 2 or more documents to concatenate
2. The user selects what pages they want to include in the TOC
3. The documents are concatenated together and a table of contents is generated

Now I am able to easily concatenate the documents and add bookmarks/outlines in PDFsharp. Where I have run into problems is when using MigraDoc to create the TOC referencing the PDFsharp created bookmarks/outlines as the targets of the hyperlinks.

Code to add bookmark/outline in PDFsharp (successfully adds the bookmarks):

// Current document is a PdfDocument and Title is the name of the bookmark
CurrentDocument.Outlines.Add(title, page, true, PdfOutlineStyle.Bold);

MigraDoc code to create the TOC page and render it to the current PDFsharp document:

// Create blank page
            PdfPage page = (!hasTitlePage)
                ? AddPage(null, 0, TOC_BOOKMARK_TITLE) // Add to start
                : AddPage(null, 1, TOC_BOOKMARK_TITLE); // Add after title page

            // Get Graphics obj
            XGraphics gfx = XGraphics.FromPdfPage(page);
            gfx.MUH = PdfFontEncoding.Unicode;

            // Create MigraDoc document + Setup styles
            Document document = new Document();
            DefineStyles(document);

            // Add header
            Section section = document.AddSection();
            Paragraph paragraph = section.AddParagraph("Table of Contents");
            paragraph.Format.Font.Size = 14;
            paragraph.Format.Font.Bold = true;
            paragraph.Format.SpaceAfter = 24;
            paragraph.Format.OutlineLevel = OutlineLevel.Level1;

            // Add links - these are the PdfSharp outlines/bookmarks added previously when concatinating the pages
            foreach (var bookmark in CurrentDocument.Outlines)
            {
                paragraph = section.AddParagraph();
                paragraph.Style = "TOC";
                Hyperlink hyperlink = paragraph.AddHyperlink(bookmark.Title);
                hyperlink.AddText($"{bookmark.Title}\t");
                hyperlink.AddPageRefField(bookmark.Title);
            }

            // Render document
            DocumentRenderer docRenderer = new DocumentRenderer(document);
            docRenderer.PrepareDocument();
            docRenderer.RenderPage(gfx, 1);

            return page;

Note - the MigraDoc code adds the TOC page but it doesn't recognize the PDFsharp bookmarks.

Screenshot of the TOC: The TOC page is added at the start (although the TOC bookmark is listed at the end) but I cannot link to PDFsharp bookmarks

I am certain that the issue is with my understanding of MigraDoc and/or PDFsharp.

First prize would be to only use PDFsharp to add the TOC. I would appreciate any help in being pointed in the right direction.

Answer 1

MigraDoc is a world of its own - it uses PDFsharp to create PDF files, but cannot access internals of PDF files creates with PDFsharp (like Bookmarks in your case).

One approach: create the TOC with PDFsharp (as you already suggested).

Other approach: use MigraDoc to add pages from existing PDF files to a MigraDoc document to create the final PDF (you can add pages from PDF files like you add images).

With the second approach you can use the formatting capabilities of MigraDoc for the TOC and MigraDoc will insert the correct page numbers, provided you add MigraDoc Bookmarks for every image (imported PDF page).

With the first approach, you will have to do the formatting and insert the page numbers yourself, but you'll have more control over the final PDF.

Which is the "best" approach? Depends a bit on the extent of formatting you need for your TOC. With the second approach the TOC can have two or more pages and MigraDoc will take care of that automatically and entries in the TOC can have two or more lines and MigraDoc will also take care of that automatically. But I think a hack will be needed to add the Outlines (e.g. draw very small white text with the outline text somewhere on the page).

Update: For the PDFsharp only approach, you will add links with code like this:

PdfRectangle prect = new PdfRectangle(gfx.Transformer.WorldToDefaultPage(rect));
page.AddDocumentLink(prect, 1);

The second parameter to AddDocumentLink is the target page.