Add TOC in PDF using C# - Document.ProcessParagraphs function duplicates the title of TOC page

Aspose.PDF Product Family
1

I found that if I insert a TextFragment that contains text for more than 1 page, and add page number stamp to each page, the page number is only added to the first page and the Document.Page.Count isn’t calculated correctly:

var pdfDocument = new Document();
var tocPage = pdfDocument.Pages.Add();
tocPage.TocInfo = new TocInfo{Title = new TextFragment("Table of Content")};

var firstPage = pdfDocument.Pages.Add();

// Generate a 200 line text.
var longText = string.Concat(Enumerable.Range(0, 200).Select(i => i + Environment.NewLine));

firstPage.Paragraphs.Add(new TextFragment(longText));
pdfDocument.ProcessParagraphs();
tocPage.Paragraphs.Add(new Heading(1)
{
    TocPage = tocPage,
    DestinationPage = firstPage,
    Segments = {new TextSegment {Text = "Main content section"}}
});
firstPage.AddStamp(new PageNumberStamp());

var secondPage = pdfDocument.Pages.Add();
secondPage.Paragraphs.Add(new TextFragment("Total page count: " + pdfDocument.Pages.Count));
tocPage.Paragraphs.Add(new Heading(1)
{
    TocPage = tocPage,
    DestinationPage = secondPage,
    Segments = {new TextSegment {Text = "Total page count section"}}
});
secondPage.AddStamp(new PageNumberStamp());

After some research, I found an Aspose blog post back in 2015 saying that calling Document.ProcessParagraphs function can force the generation of the pages, so I updated my code to call this function:

var pdfDocument = new Document();
var tocPage = pdfDocument.Pages.Add();
tocPage.TocInfo = new TocInfo{Title = new TextFragment("Table of Content")};

var firstPage = pdfDocument.Pages.Add();

// Generate a 200 line text.
var longText = string.Concat(Enumerable.Range(0, 200).Select(i => i + Environment.NewLine));

firstPage.Paragraphs.Add(new TextFragment(longText));

// Call this to force page generation.
pdfDocument.ProcessParagraphs();

tocPage.Paragraphs.Add(new Heading(1)
{
    TocPage = tocPage,
    DestinationPage = firstPage,
    Segments = {new TextSegment {Text = "Main content section"}}
});

var secondPage = pdfDocument.Pages.Add();
secondPage.Paragraphs.Add(new TextFragment("Total page count: " + pdfDocument.Pages.Count));
tocPage.Paragraphs.Add(new Heading(1)
{
    TocPage = tocPage,
    DestinationPage = secondPage,
    Segments = {new TextSegment {Text = "Total page count section"}}
});

foreach (var page in pdfDocument.Pages)
{
    page.AddStamp(new PageNumberStamp());
}

This fixes the incorrect page count but it duplicates the title of the table of content page (TocInfo.Title).

After some testing, I found that each time the Document.ProcessParagraphs function is called, it duplicates the title of the table of content page once more.

I’d like to know how I can generate a table of content page without duplicating the title, while keeping the page number and page count correct in this case.

2

@leon.zhou

Please try to call ProcessParagraphs() method before adding the TOC page. In other words, it is better to create TOC Page after finalizing other PDF Pages. Try to use the below modified code snippet to get correct results:

var pdfDocument = new Document();

var firstPage = pdfDocument.Pages.Add();

// Generate a 200 line text.
var longText = string.Concat(Enumerable.Range(0, 200).Select(i => i + Environment.NewLine));

firstPage.Paragraphs.Add(new TextFragment(longText));

// Call this to force page generation.
pdfDocument.ProcessParagraphs();

var tocPage = pdfDocument.Pages.Insert(1);
tocPage.TocInfo = new TocInfo { Title = new TextFragment("Table of Content") };

tocPage.Paragraphs.Add(new Heading(1)
{
 TocPage = tocPage,
 DestinationPage = firstPage,
 Segments = { new TextSegment { Text = "Main content section" } }
});

var secondPage = pdfDocument.Pages.Add();
secondPage.Paragraphs.Add(new TextFragment("Total page count: " + pdfDocument.Pages.Count));
tocPage.Paragraphs.Add(new Heading(1)
{
 TocPage = tocPage,
 DestinationPage = secondPage,
 Segments = { new TextSegment { Text = "Total page count section" } }
});

foreach (var page in pdfDocument.Pages)
{
 page.AddStamp(new PageNumberStamp());
}
pdfDocument.Save(dataDir + "simpletoc.pdf");
3

Hi @asad.ali, thank you for your reply. This works great for me!

4

@leon.zhou

It is nice to hear that your issue has been resolved. Please feel free to create a new topic in case you need further assistance.