Where does IPdfTextObjectCollection live in the IronPDF API?

IPdfTextObjectCollection is in the IronSoftware namespace, shipped in IronPdf.dll. It extends IDocumentTextObjectCollection , IList , ICollection , IEnumerable , and IJsonSerializable. The concrete implementor is IronSoftware.TextObjectCollection, the type returned by PdfPage.Lines and PdfPage.TextChunks over TextObject elements.

What implements IPdfTextObjectCollection in IronPDF?

The concrete class IronSoftware.TextObjectCollection implements IPdfTextObjectCollection. TextObjectCollection extends ObservableCollection and adds the IsReadOnly and Items properties along with the Add(TextObject), Remove(TextObject), RemoveAt(Int32), Clear, GetHashCode, and ToJson methods. Instances flow out of the IronPDF page model rather than being constructed directly: IronPdf.Pages.PdfPage.Lines and IronPdf.Pages.PdfPage.TextChunks both return IPdfTextObjectCollection, with Lines providing per-visual-line grouping and TextChunks providing per-text-run granularity. Application code typically declares the variable as IPdfTextObjectCollection and casts to TextObjectCollection only when ObservableCollection change notifications are required.

Is the collection returned by PdfPage.Lines a live view of the page?

The IPdfTextObjectCollection returned by PdfPage.Lines is a freshly-grouped snapshot, not a live view of page state. The docfx remarks describe Lines as derived from TextChunks by grouping text objects that appear on the same visual line based on their vertical position, so each access re-runs the grouping over the current TextChunks. Mutating the returned collection through Add, Remove, or Clear modifies the snapshot, and another call to PdfPage.Lines on the same page returns a new collection that reflects the underlying TextChunks again. For round-trip edits, work through the write-side API such as ReplaceTextOnPage rather than mutating the snapshot.

How do you extract every text line on a page along with its position?

Open the PDF through PdfDocument.FromFile, iterate PdfDocument.Pages to get each PdfPage, and read PdfPage.Lines to receive the IPdfTextObjectCollection for that page. Read the Count property to size any output buffer, then index into the collection or iterate it with foreach to receive TextObject elements. Each TextObject exposes Contents for the line text, BoundingBox for the page-space position, and PageIndex for the zero-based page index. When sub-line per-run geometry is required, read PdfPage.TextChunks instead, since Lines is derived from TextChunks by vertical-position grouping.

Interface IPdfTextObjectCollection

Collection of PDF text objects

Namespace: IronSoftware

Assembly: IronPdf.dll

Syntax

public interface IPdfTextObjectCollection : IDocumentTextObjectCollection<TextObject>, IEnumerable<TextObject>, IEnumerable, IList<TextObject>, ICollection<TextObject>, IJsonSerializable

Reading a page's text DOM as a list of IronSoftware.TextObject elements runs through IPdfTextObjectCollection, the value returned from IronPdf.Pages.PdfPage.Lines and IronPdf.Pages.PdfPage.TextChunks. Every list operation defined on IList<T> is available on instances returned from the IronPDF page model.

IPdfTextObjectCollection is the type a caller works with whenever code reads or rewrites the per-line or per-run text DOM of a page. Typical scenarios include enumerating each line on a page to reconstruct columns during PDF layout analysis, indexing into a specific line to read its Contents and BoundingBox during search-result highlighting, and counting text runs on a page before deciding whether to call PdfExtractor or to walk the DOM directly. The contract is paired with the concrete IronSoftware.TextObjectCollection (an ObservableCollection<TextObject> that implements this interface), and sits alongside IPdfImageObjectCollection and IPdfPathObjectCollection as the three page-DOM containers in the IronSoftware namespace.

To consume IPdfTextObjectCollection, open a PdfDocument, enumerate PdfDocument.Pages, and access PdfPage.Lines for line-level grouping or PdfPage.TextChunks for per-run granularity. The contract carries no declarations of its own; every callable member is inherited from IList<TextObject> (the indexer this[int], Count, Contains, IndexOf, CopyTo), ICollection<TextObject> (Add, Remove, RemoveAt, Clear, IsReadOnly), and IJsonSerializable (ToJson). The docfx remarks describe PdfPage.Lines as "derived from TextChunks by grouping text objects that appear on the same visual line based on their vertical position", so each access returns a freshly-grouped collection rather than a live view of page state. For the surrounding extraction workflow, see the extract text and images how-to.

using IronPdf;
using IronPdf.Pages;
using IronSoftware;

PdfDocument pdf = PdfDocument.FromFile("invoice.pdf");

foreach (PdfPage page in pdf.Pages)
{
    IPdfTextObjectCollection lines = page.Lines;
    System.Console.WriteLine($"Page {page.PageNumber}: {lines.Count} lines");

    for (int i = 0; i < lines.Count; i++)
    {
        TextObject line = lines[i];
        System.Console.WriteLine($"  [{i}] \"{line.Contents}\" at {line.BoundingBox}");
    }
}

Walking the sibling IPdfImageObjectCollection and IPdfPathObjectCollection containers in the same pass is shown in the access PDF DOM object how-to. When the goal is editing text in place rather than enumerating the line collection, the find and replace text in PDF how-to has worked ReplaceTextOnAllPages and ReplaceTextOnPage examples.