Class PdfBookMarkCollection

Manages a collection of PDF bookmarks (document outline) for navigation. Supports adding, removing, and traversing bookmarks in a hierarchical structure.

Access the root collection via Bookmarks. Each bookmark can have its own Children collection for nested entries.

Example - Build complete document outline:

var pdf = PdfDocument.FromFile("manual.pdf");

// Create root-level chapters:
var intro = pdf.Bookmarks.AddBookMarkAtEnd("Introduction", 0);
var basics = pdf.Bookmarks.AddBookMarkAtEnd("Basic Concepts", 5);
var advanced = pdf.Bookmarks.AddBookMarkAtEnd("Advanced Topics", 20);


// Add nested sections:
intro.Children.AddBookMarkAtEnd("Welcome", 0);
intro.Children.AddBookMarkAtEnd("Getting Started", 2);


basics.Children.AddBookMarkAtEnd("Core Features", 5);
basics.Children.AddBookMarkAtEnd("Configuration", 10);


// List all bookmarks:
foreach (var bm in pdf.Bookmarks.GetAllBookmarks())
Console.WriteLine($"{bm.Text} → Page {bm.PageIndex + 1}");


pdf.SaveAs("manual_with_outline.pdf");

Inheritance
System.Object
PdfClientAccessor
PdfBookMarkCollection
Implements
System.Collections.Generic.IEnumerable<IronPdf.Bookmarks.IPdfBookmark>
System.Collections.IEnumerable
Namespace: IronPdf.Bookmarks
Assembly: IronPdf.dll
Syntax
public class PdfBookMarkCollection : PdfClientAccessor, IPdfBookMarkCollection

PDF bookmarks in IronPDF is handled through PdfBookMarkCollection. It manages a collection of PDF bookmarks (document outline) for navigation.

PdfBookMarkCollection matters when an application needs to configure or invoke PDF bookmarks from C# code. The class encapsulates the related options and behavior in a single object that is set up once and reused across render or processing calls. Typical scenarios include batch generation pipelines, templated document workflows, and integration with existing C# document services.

To use PdfBookMarkCollection, instantiate or obtain it from the relevant entry point in the IronPDF C# API. Key properties include Count, FirstBookmark, LastBookmark, Parent. Assign options or invoke methods on the instance to configure or perform the operation. The access PDF DOM object covers typical usage in C# end to end.

using IronPdf;

// Obtain PdfBookMarkCollection from the relevant entry point in the IronPDF API
void Configure(PdfBookMarkCollection instance)
{
    var current = instance.Count;
    instance.AddBookMarkAtEnd();
}

For the broader workflow, see the bookmarks guide in the IronPDF C# documentation. For broader context, the PDF bookmarks portion of the IronPDF C# API contains related types that work with PdfBookMarkCollection directly. PdfBookMarkCollection instances inherit additional members from PdfClientAccessor that may be relevant in advanced scenarios. In application code, treat PdfBookMarkCollection as a configured object that is constructed once and reused across operations rather than instantiated per call. Configuration is generally idempotent: assigning the same property value twice has the same effect as assigning it once. For diagnostic purposes, inspect the relevant PdfBookMarkCollection property after each operation to confirm the configured state. See the constructors, properties, and methods tables below for the complete API surface of PdfBookMarkCollection. Application code typically obtains or instantiates a single PdfBookMarkCollection and shares it across multiple IronPDF operations rather than recreating it per call.

Properties

Count

Total number of bookmarks, including all nested bookmarks

Declaration
public int Count { get; }
Property Value
Type Description
System.Int32

FirstBookmark

First bookmark within the bookmark collection at the current level

Declaration
public IPdfBookmark FirstBookmark { get; }
Property Value
Type Description
IronPdf.Bookmarks.IPdfBookmark

LastBookmark

Last bookmark within the bookmark collection at the current level

Declaration
public IPdfBookmark LastBookmark { get; }
Property Value
Type Description
IronPdf.Bookmarks.IPdfBookmark

Parent

Bookmark which contains this bookmark collection

Declaration
public IPdfBookmark Parent { get; }
Property Value
Type Description
IronPdf.Bookmarks.IPdfBookmark

Methods

AddBookMarkAtEnd(String, Int32)

Add a new bookmark at the end of this bookmark collection

Declaration
public IPdfBookmark AddBookMarkAtEnd(string text, int pageIndex)
Parameters
Type Name Description
System.String text

The display text for the link.
System.Int32 pageIndex

The zero based page number to link to. E.g. Page 1 has a PageIndex of 0
Returns
Type Description
IronPdf.Bookmarks.IPdfBookmark

Newly added bookmark

AddBookMarkAtStart(String, Int32)

Add a new bookmark at the start of this bookmark collection

Declaration
public IPdfBookmark AddBookMarkAtStart(string text, int pageIndex)
Parameters
Type Name Description
System.String text

The display text for the link.
System.Int32 pageIndex

The zero based page number to link to. E.g. Page 1 has a PageIndex of 0
Returns
Type Description
IronPdf.Bookmarks.IPdfBookmark

Newly added bookmark

GetAllBookmarks()

Retrieve all bookmarks within this collection, recursively retrieve all children of bookmarks within this collection, and return a flat list

Declaration
public List<IPdfBookmark> GetAllBookmarks()
Returns
Type Description
System.Collections.Generic.List<IronPdf.Bookmarks.IPdfBookmark>

A flattened list of all bookmarks in this collection and all of their children

GetBookmarkAfter(IPdfBookmark)

Retrieve the next bookmark after the specified bookmark at the current level

Declaration
public IPdfBookmark GetBookmarkAfter(IPdfBookmark previousBookmark)
Parameters
Type Name Description
IronPdf.Bookmarks.IPdfBookmark previousBookmark

Previous bookmark
Returns
Type Description
IronPdf.Bookmarks.IPdfBookmark

Next bookmark at the current level

GetBookmarkBefore(IPdfBookmark)

Retrieve the previous bookmark before the specified bookmark at the current level

Declaration
public IPdfBookmark GetBookmarkBefore(IPdfBookmark nextBookmark)
Parameters
Type Name Description
IronPdf.Bookmarks.IPdfBookmark nextBookmark

Next bookmark
Returns
Type Description
IronPdf.Bookmarks.IPdfBookmark

Previous bookmark at the current level

GetEnumerator()

Declaration
public IEnumerator<IPdfBookmark> GetEnumerator()
Returns
Type Description
System.Collections.Generic.IEnumerator<IronPdf.Bookmarks.IPdfBookmark>

InsertBookMarkAfter(String, Int32, IPdfBookmark)

Insert a new bookmark after the specified bookmark

Declaration
public IPdfBookmark InsertBookMarkAfter(string text, int pageIndex, IPdfBookmark previousBookmark)
Parameters
Type Name Description
System.String text

The display text for the link.
System.Int32 pageIndex

The zero based page number to link to. E.g. Page 1 has a PageIndex of 0
IronPdf.Bookmarks.IPdfBookmark previousBookmark

Bookmark after which to insert a new bookmark
Returns
Type Description
IronPdf.Bookmarks.IPdfBookmark

InsertBookMarkBefore(String, Int32, IPdfBookmark)

Insert a new bookmark before the specified bookmark

Declaration
public IPdfBookmark InsertBookMarkBefore(string text, int pageIndex, IPdfBookmark nextBookmark)
Parameters
Type Name Description
System.String text

The display text for the link.
System.Int32 pageIndex

The zero based page number to link to. E.g. Page 1 has a PageIndex of 0
IronPdf.Bookmarks.IPdfBookmark nextBookmark

Bookmark before which to insert a new bookmark
Returns
Type Description
IronPdf.Bookmarks.IPdfBookmark

RemoveBookMark(IPdfBookmark)

Removes the specified bookmark from this bookmark collection

Declaration
public void RemoveBookMark(IPdfBookmark bookmark)
Parameters
Type Name Description
IronPdf.Bookmarks.IPdfBookmark bookmark

The bookmark object to remove.

RemoveBookMarkAt(Int32)

Removes a bookmark at the specified index from this bookmark collection or any of its children

Declaration
public void RemoveBookMarkAt(int index)
Parameters
Type Name Description
System.Int32 index

The index of the bookmark to remove.

Implements

System.Collections.Generic.IEnumerable<>
System.Collections.IEnumerable

See Also