Which namespace and assembly contain TextAnnotation?

TextAnnotation is in the IronPdf.Annotations namespace, shipped in IronPdf.dll. It derives from PdfClientAccessor.

What are the key properties of TextAnnotation?

Properties commonly used on TextAnnotation include AnnotationIndex, Color, Contents, Height. Each property configures one aspect of the PDF annotations surface exposed by the class.

How do you create a TextAnnotation in C#?

Instantiate TextAnnotation directly with one of its constructors, or obtain it from the relevant IronPDF API entry point. The class supports the standard C# new expression where a constructor is defined.

Class TextAnnotation

Q: What is the TextAnnotation class used for in C#?

TextAnnotation is the IronPDF class that creates interactive sticky-note annotations for PDF documents - like Post-itÂ® notes for digital documents. It is part of the IronPdf.Annotations namespace and is used through the IronPDF C# API.

Creates interactive sticky-note annotations for PDF documents - like Post-itÂ® notes for digital documents. Perfect for comments, review feedback, and collaborative document workflows.

// Add simple comment:
var comment = new TextAnnotation(0, "Review", "Please check figures") {
    X = 100, Y = 100,
    Color = Color.Yellow
};
pdf.Annotations.Add(comment);

// Review annotation with metadata:
var review = new TextAnnotation(pageIndex: 0) {
    Title = "John Smith",
    Subject = "Technical Review",
    Contents = "Algorithm needs optimization",
    X = 300, Y = 500,
    Color = Color.Red,
    OpenByDefault = true
};
pdf.Annotations.Add(review);

// Hidden annotation for metadata:
var metadata = new TextAnnotation(0, "Version", "v2.1.0") {
    Hidden = true,
    Printable = false
};
pdf.Annotations.Add(metadata);

Annotations appear as icons that expand to show full text

Some PDF viewers may not respect all properties

See: https://ironpdf.com/how-to/annotations/

Inheritance

System.Object

PdfClientAccessor

TextAnnotation

Implements

IAnnotation

Namespace: IronPdf.Annotations

Assembly: IronPdf.dll

Syntax

public class TextAnnotation : PdfClientAccessor, IAnnotation

Working with PDF annotations in IronPDF runs through TextAnnotation. It creates interactive sticky-note annotations for PDF documents - like Post-itÂ® notes for digital documents.

TextAnnotation matters when an application needs to configure or invoke PDF annotations 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 TextAnnotation, instantiate or obtain it from the relevant entry point in the IronPDF C# API. Key properties include AnnotationIndex, Color, Contents, Height. Assign options or invoke methods on the instance to configure or perform the operation. The annotations covers typical usage in C# end to end.

using IronPdf;

// Obtain TextAnnotation from the relevant entry point in the IronPDF API
void Configure(TextAnnotation instance)
{
    var current = instance.AnnotationIndex;
    instance.ToString();
}

For the broader workflow, see the color grayscale guide in the IronPDF C# documentation. For broader context, the PDF annotations portion of the IronPDF C# API contains related types that work with TextAnnotation directly. TextAnnotation instances inherit additional members from PdfClientAccessor that may be relevant in advanced scenarios. In application code, treat TextAnnotation 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 TextAnnotation property after each operation to confirm the configured state. See the constructors, properties, and methods tables below for the complete API surface of TextAnnotation. Application code typically obtains or instantiates a single TextAnnotation and shares it across multiple IronPDF operations rather than recreating it per call.

Constructors

TextAnnotation(Int32)

Define a new annotation with the specified parameters. Annotation must be added to the document via PdfDocument.Annotations

Declaration

public TextAnnotation(int PageIndex)

Parameters

Type	Name	Description
System.Int32	PageIndex	Page index

TextAnnotation(Int32, String, String)

Define a new annotation with the specified parameters. Annotation must be added to the document via PdfDocument.Annotations

Declaration

public TextAnnotation(int PageIndex, string Title, string Contents)

Parameters

Type	Name	Description
System.Int32	PageIndex	Page index
System.String	Title	Annotation title
System.String	Contents	Annotation contents

TextAnnotation(String, String)

Define a new annotation with the specified parameters. Annotation must be added to the document via PdfDocument.Annotations

Declaration

public TextAnnotation(string Title, string Contents)

Parameters

Type	Name	Description
System.String	Title	Annotation title
System.String	Contents	Annotation contents

Properties

AnnotationIndex

Gets or sets the zero-based index of this annotation on its page. Used internally to identify the annotation. Value of -1 indicates not yet added to document.

Declaration

public int AnnotationIndex { get; set; }

Property Value

Type	Description
System.Int32	Annotation index, or -1 if not added to document.

Color

The color of the annotation's 'Sticky Note' Note: Google Chrome PDF Viewer may not respect this color.
However, Adobe PDF Viewer and Foxit PDF Viewer display the color correctly.

Declaration

public Color Color { get; set; }

Property Value

Type	Description
IronSoftware.Drawing.Color

The contents of the 'sticky note' annotation

Declaration

public string Contents { get; set; }

Property Value

Type	Description
System.String

Height

Annotation visible height Note: Google Chrome or Adobe PDF Viewer may not respect this height.
However, Foxit PDF Viewer handles the height correctly.

Declaration

public int Height { get; set; }

Property Value

Type	Description
System.Int32

Hidden

Hides the annotation from users

Declaration

public bool Hidden { get; set; }

Property Value

Type	Description
System.Boolean

Opacity

The opacity of the annotation (valid values are from 0.0 to 1.0)

Declaration

public double Opacity { get; set; }

Property Value

Type	Description
System.Double

OpenByDefault

Sets the annotation to be opened and readable by default, without user interaction

Declaration

public bool OpenByDefault { get; set; }

Property Value

Type	Description
System.Boolean

PageIndex

Gets or sets the zero-based page index where this annotation appears. Page 1 = index 0, Page 2 = index 1, etc. (default: 0 - first page).

Declaration

public int PageIndex { get; set; }

Property Value

Type	Description
System.Int32	Zero-based page index (default: 0).

Printable

Allows the annotation to be printed when users print the PDF

Declaration

public bool Printable { get; set; }

Property Value

Type	Description
System.Boolean

ReadOnly

Allows the annotation to be printed when users print the PDF

Declaration

public bool ReadOnly { get; set; }

Property Value

Type	Description
System.Boolean

Rectangle

The position and size of annotation.
Note: Google Chrome or Adobe PDF Viewer may not respect the width and height.
However, Foxit PDF Viewer handles the position and size correctly.

Declaration

public Rectangle Rectangle { get; set; }

Property Value

Type	Description
IronSoftware.Drawing.Rectangle

Rotatable

Allows the annotation to be rotated. E.g. when the containing page os rotated

Declaration

public bool Rotatable { get; set; }

Property Value

Type	Description
System.Boolean

Subject

The sub title of the annotation as displayed in the header of the 'sticky note'

Declaration

public string Subject { get; set; }

Property Value

Type	Description
System.String

Title

The main title of the annotation as displayed in the header of the 'sticky note'

Declaration

public string Title { get; set; }

Property Value

Type	Description
System.String

Width

Annotation visible width Note: Google Chrome or Adobe PDF Viewer may not respect this width.
However, Foxit PDF Viewer handles the width correctly.

Declaration

public int Width { get; set; }

Property Value

Type	Description
System.Int32

X

Gets or sets the horizontal X position from the LEFT edge of the page, in points. 72 points = 1 inch. Example: X = 72 positions annotation 1 inch from left edge.

Example:

annotation.X = 100;  // 100 points from left edge

Declaration

public int X { get; set; }

Property Value

Type	Description
System.Int32	Horizontal position in points from left edge (default: -1 if not set).

Y

Gets or sets the vertical Y position from the BOTTOM edge of the page, in points. 72 points = 1 inch. PDF coordinate system places Y=0 at bottom of page.

Example:

// Position annotation 2 inches from bottom:
annotation.Y = 144;  // 144 points = 2 inches
// Top of an 11-inch page (Letter size):
annotation.Y = 792;  // 11 Ã— 72 = 792 points

Declaration

public int Y { get; set; }

Property Value

Type	Description
System.Int32	Vertical position in points from bottom edge (default: -1 if not set).

Methods

ToString()

Returns a System.String that represents this annotation.

Declaration

public override string ToString()

Returns

Type	Description
System.String	A System.String that represents this instance.

Implements

IAnnotation