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Create a Table of Contents for Merged PDF Documents

Updated on Mar 17, 2026

Environment

Version	Product	Author
2026.1.304	RadPdfProcessing	Yoan Karamanov

This article describes how to merge multiple PDF documents into a single file and then add a Table of Contents (TOC) page at the beginning of the merged document. Each TOC entry is a clickable link that navigates to the first page of the respective source document.

Solution

The TOC must be created after all source documents have been merged. The key considerations are:

The FixedContentEditor requires manual position calculations when placing content elements on a page.
Use the Measure method of the Block to determine whether the next TOC entry will exceed the page boundary. If so, insert a new TOC page and continue from there.
Track the start page index of each source document before merging, so you can later build accurate Link annotations using a GoToAction pointing to the correct RadFixedPage.
When new TOC pages are inserted at the beginning of the RadFixedDocument, adjust the target page index by the number of TOC pages added.

The following example demonstrates the complete approach:

Merge PDF files and create a TOC

csharp

static void Main(string[] args)
{
    string sourceDirectory = @"..\..\..\PDF files";
    string outputFile = @"..\..\..\MergedOutput.pdf";

    MergePdfFiles(sourceDirectory, outputFile);
}

static void MergePdfFiles(string sourceDirectory, string outputFile)
{
    string[] pdfFiles = Directory.GetFiles(sourceDirectory, "*.pdf", SearchOption.TopDirectoryOnly);

    if (pdfFiles.Length == 0)
    {
        return;
    }

    RadFixedDocument mergedDocument = new RadFixedDocument();
    PdfFormatProvider formatProvider = new PdfFormatProvider();

    var documentStartPages = new System.Collections.Generic.List<System.Tuple<string, int>>();

    foreach (string pdfFile in pdfFiles.OrderBy(f => f))
    {
        int startPageIndex = mergedDocument.Pages.Count;
        string fileName = Path.GetFileNameWithoutExtension(pdfFile);

        RadFixedDocument sourceDocument;
        using (FileStream fileStream = File.OpenRead(pdfFile))
        {
            sourceDocument = formatProvider.Import(fileStream);
        }

        mergedDocument.Merge(sourceDocument);

        documentStartPages.Add(System.Tuple.Create(fileName, startPageIndex));
    }

    CreateTOC(mergedDocument, documentStartPages);

    using (FileStream outputStream = File.Create(outputFile))
    {
        formatProvider.Export(mergedDocument, outputStream);
    }
}

static void CreateTOC(RadFixedDocument document, System.Collections.Generic.List<System.Tuple<string, int>> documentStartPages)
{
    RadFixedPage currentTocPage = new RadFixedPage();
    document.Pages.Insert(0, currentTocPage);

    FixedContentEditor editor = new FixedContentEditor(currentTocPage);

    int factor = 20;
    int offsetX = 70;
    int currentY = 20;
    int tocPageIndex = 0;

    foreach (var docInfo in documentStartPages)
    {
        Block block = new Block();
        block.GraphicProperties.FillColor = new RgbColor(255, 5, 99, 193);
        block.InsertText($"{docInfo.Item1} - Page {docInfo.Item2 + 1}");
        Size blockSize = block.Measure();

        if (currentY + blockSize.Height > currentTocPage.Size.Height - 20)
        {
            tocPageIndex++;
            currentTocPage = new RadFixedPage();
            document.Pages.Insert(tocPageIndex, currentTocPage);
            editor = new FixedContentEditor(currentTocPage);
            currentY = 20;
        }

        editor.Position.Translate(offsetX, currentY);
        editor.DrawBlock(block);

        int adjustedPageIndex = docInfo.Item2 + tocPageIndex + 1;
        RadFixedPage targetPage = document.Pages[adjustedPageIndex];

        Location location = new Location
        {
            Left = 0,
            Top = 0,
            Zoom = 0,
            Page = targetPage
        };

        GoToAction goToAction = new GoToAction();
        goToAction.Destination = location;

        Link link = currentTocPage.Annotations.AddLink(goToAction);
        link.Rect = new Rect(offsetX, currentY, blockSize.Width, blockSize.Height);

        currentY += factor;
    }
}

Notes

The documentStartPages list records the zero-based start page index of each source document before it is merged. This ensures correct navigation targets even after the TOC pages are prepended.
The adjustedPageIndex calculation (docInfo.Item2 + tocPageIndex + 1) compensates for the TOC pages that are inserted before the merged content.
Each TOC entry is drawn as a Block and wrapped in a Link annotation whose rectangle exactly matches the measured block bounds.

Create a Table of Contents for Merged PDF Documents

Environment

Description

Solution

Merge PDF files and create a TOC

Notes

See Also