Where does PdfLayerCollection live in the IronPDF API?

PdfLayerCollection is a class in the IronSoftware namespace, shipped in IronPdf.dll. It extends ReadOnlyCollection and is obtained from a PdfDocument's Layers property.

How do you find a specific PDF layer by name in C#?

Call FindByName on a PdfLayerCollection, passing the layer's string name. Use FindById instead when you have the integer id. To retrieve all children of a layer, pass its id to ChildrenOf, which returns an IEnumerable .

Class PdfLayerCollection

Read-only collection of PdfLayer entries for a PDF document. Exposes helpers for the two operations callers actually do with the layer tree: lookup by id and lookup by name.

Inheritance

System.Object

PdfLayerCollection

Namespace: IronSoftware

Assembly: IronPdf.dll

Syntax

public class PdfLayerCollection : ReadOnlyCollection<PdfLayer>

Navigating a PDF's optional content groups becomes straightforward with PdfLayerCollection, a read-only handle that wraps the document's full layer tree and exposes targeted lookup helpers. Extending ReadOnlyCollection<PdfLayer>, it preserves the integrity of the layer structure while giving callers two direct retrieval paths and one tree-traversal method.

FindById locates a single PdfLayer by its integer identifier, the fastest route when the id is already known from a prior inspection pass. FindByName accepts a string and returns the matching layer, useful when working from human-readable layer names embedded in a PDF's metadata. ChildrenOf takes a parent id and returns an IEnumerable<PdfLayer> of all direct children, letting you walk nested layer groups without manually filtering the full collection. Together, these three members cover the two everyday tasks: pinpointing a specific layer and understanding the hierarchy beneath a given node.

Because PdfLayerCollection derives from ReadOnlyCollection<PdfLayer>, standard LINQ queries work directly on it alongside the dedicated helpers. You can, for example, call ChildrenOf to get a subtree and then apply .Where or .Select to that result without any additional conversion.

using IronPdf;

PdfDocument pdf = PdfDocument.FromFile("layered.pdf");
PdfLayerCollection layers = pdf.Layers;

PdfLayer background = layers.FindByName("Background");
foreach (PdfLayer child in layers.ChildrenOf(background.Id))
    Console.WriteLine(child.Name);

For broader context on working with PDF layers in IronPDF, see the PDF layers how-to and the IronPDF examples library.

Methods

ChildrenOf(Int32)

Enumerate the direct children of a layer in the document's /OCProperties/D/Order tree. Pass -1 to enumerate root layers.

Declaration

public IEnumerable<PdfLayer> ChildrenOf(int parentId)

Parameters

Type	Name	Description
System.Int32	parentId

Returns

Type	Description
System.Collections.Generic.IEnumerable<PdfLayer>

FindById(Int32)

Find a layer by its stable OCG id (the value carried on TextObject.OcgId / PathObject.OcgId). Returns null for unknown ids and for the sentinel -1 ("no layer").

Declaration

public PdfLayer FindById(int id)

Parameters

Type	Name	Description
System.Int32	id

Returns

Type	Description
PdfLayer

FindByName(String)

Find the first layer whose /Name matches. Comparison is exact and case-sensitive.

Declaration

public PdfLayer FindByName(string name)

Parameters

Type	Name	Description
System.String	name

Returns

Type	Description
PdfLayer