How to create Table Of Contents in iTextSharp

You've probably implemented this yourself by name, but I made a small example myself for the sake of completeness.

Please take a look at the CreateTOC example. It creates a PDF with some random text:

You can clearly see the titles and the content under the titles. After we have added all our content, we start a new page, and we add a table of contents:

The table of contents is composed by a series of key-value pairs, where the key is the title and the value is the page number. We create this list in a page event:

public class TOCEvent extends PdfPageEventHelper {

    protected List<SimpleEntry<String, Integer>> toc = new ArrayList<>();

    @Override
    public void onGenericTag(PdfWriter writer, Document document, Rectangle rect, String text) {
        toc.add(new SimpleEntry(text, writer.getPageNumber()));
    }

    public List getTOC() {
        return toc;
    }
}

We use this page event like this:

public void createPdf(String dest) throws IOException, DocumentException {
    Document document = new Document();
    PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(dest));
    TOCEvent event = new TOCEvent();
    writer.setPageEvent(event);
    document.open();
    for (int i = 0; i < 10; i++) {
        String title = "This is title " + i;
        Chunk c = new Chunk(title, titleFont);
        c.setGenericTag(title);
        document.add(new Paragraph(c));
        for (int j = 0; j < 50; j++) {
            document.add(new Paragraph("Line " + j + " of title " + i));
        }
    }
    document.newPage();
    document.add(new Paragraph("Table of Contents", titleFont));
    Chunk dottedLine = new Chunk(new DottedLineSeparator());
    List<SimpleEntry<String, Integer>> entries = event.getTOC();
    Paragraph p;
    for (SimpleEntry<String, Integer> entry : entries) {
        p = new Paragraph(entry.getKey());
        p.add(dottedLine);
        p.add(String.valueOf(entry.getValue()));
        document.add(p);
    }
    document.close();
}

First we create an instance of the event and we declare it to the writer:

TOCEvent event = new TOCEvent();
writer.setPageEvent(event);

We mark the titles using setGenericTag():

String title = "This is title " + i;
Chunk c = new Chunk(title, titleFont);
c.setGenericTag(title);
document.add(new Paragraph(c));

Once we've finished adding the content, we get all the entries:

List<SimpleEntry<String, Integer>> entries = event.getTOC();

We loop over this list and compose a Paragraph for every entry:

for (SimpleEntry<String, Integer> entry : entries) {
    p = new Paragraph(entry.getKey());
    p.add(dottedLine);
    p.add(String.valueOf(entry.getValue()));
    document.add(p);
}

No one can argue that this was difficult. The event class takes less than 10 lines of code. Adding support for subheadings will add a handful of lines, but that shouldn't be difficult too. It's a matter of building a tree structure, and introducing some indentation where necessary.

Thanks for the example, i needed this in C# and with multicolumn, so i rewrote this example as below:

namespace GerarPDF
{
public class GerarPDF
{
    public const String DEST = "results/example.pdf";

    public GerarPDF()
    {
        FileInfo file = new FileInfo(String.Concat(AppDomain.CurrentDomain.BaseDirectory, @"/", DEST));
        file.Directory.Create();
        this.createPdf(file.FullName);
    }

    public void createPdf(String dest)
    {
        FileStream fs = new FileStream(dest, FileMode.OpenOrCreate, FileAccess.Write, FileShare.None);

        Document document = new Document(PageSize.LETTER);
        PdfWriter writer = PdfWriter.GetInstance(document, fs);
        document.Open();

        TOCEvent evento = new TOCEvent();
        writer.PageEvent = evento;

        for (int i = 0; i < 10; i++)
        {
            String title = "This is title " + i;
            Chunk c = new Chunk(title, new Font());
            c.SetGenericTag(title);
            document.Add(new Paragraph(c));
            for (int j = 0; j < 50; j++)
            {
                document.Add(new Paragraph("Line " + j + " of title " + i + " page: " + writer.PageNumber));
            }
        }
        document.NewPage();
        document.Add(new Paragraph("Table of Contents", new Font()));
        Chunk dottedLine = new Chunk(new DottedLineSeparator());
        List<PageIndex> entries = evento.getTOC();

        MultiColumnText columns = new MultiColumnText();
        columns.AddRegularColumns(72, 72 * 7.5f, 24, 2);

        Paragraph p;
        for (int i = 0; i < 10; i++)
        {
            foreach (PageIndex pageIndex in entries)
            {
                Chunk chunk = new Chunk(pageIndex.Text);
                chunk.SetAction(PdfAction.GotoLocalPage(pageIndex.Name, false));
                p = new Paragraph(chunk);
                p.Add(dottedLine);

                chunk = new Chunk(pageIndex.Page.ToString());
                chunk.SetAction(PdfAction.GotoLocalPage(pageIndex.Name, false));
                p.Add(chunk);

                columns.AddElement(p);
            }
        }
        document.Add(columns);

        document.Close();
    }

    public class TOCEvent : PdfPageEventHelper
    {
        protected int counter = 0;
        protected List<PageIndex> toc = new List<PageIndex>();

        public override void OnGenericTag(PdfWriter writer, Document document, Rectangle rect, string text)
        {
            String name = "dest" + (counter++);
            int page = writer.PageNumber;
            toc.Add(new PageIndex() { Text = text, Name = name, Page = page });
            writer.DirectContent.LocalDestination(name, new PdfDestination(PdfDestination.FITH, rect.GetTop(0)));
        }

        public List<PageIndex> getTOC()
        {
            return toc;
        }
    }
}

public class PageIndex
{
    public string Text { get; set; }
    public string Name { get; set; }
    public int Page { get; set; }
}
}