Annotations in PDF Viewer

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The PDF Viewer allows you to create, edit, or remove text annotations (sticky notes) and text markup annotations (text highlights). You can also add comments and reviews associated with annotations.


Create an Annotation

User Interface

Use commands on the Comment ribbon page to create text markup annotations and sticky notes.


Enable a selection tool in the Text group and select the text that should have an annotation. Click Sticky Note to place the sticky note in a document.


You can also add text markup annotations from the context menu:



Use the PdfViewer.CursorMode property to change the viewer’s cursor mode in code.


The following API allows you to add annotations in code:

Method Description
PdfViewer.HighlightSelectedText Highlights the selected text.
PdfViewer.StrikethroughSelectedText Strikes through the selected text.
PdfViewer.UnderlineSelectedText Underlines the selected text.
PdfViewer.AddStickyNote Adds a sticky note at the specified position.

The code below highlights the selected text and adds a sticky note.

View Example: How to create a text markup annotation

using System.Drawing;
using System.Windows.Forms;

namespace CreateMarkupAnnotation
    public partial class Form1 : Form
        public Form1()

            // Load a document.

            // Select the text where the markup annotation will be created:
            pdfViewer.FindText("PDF Viewer");

            // Highlight selected text.

            (new PdfDocumentPosition(1, new PdfPoint(29, 568)),
             "Comment", Color.Crimson);

Change Markup Tool Settings

User Interface

You can change the default settings for annotation tools. Click the drop-down arrow in the corresponding annotation tool and specify the color and opacity.



To access the markup tool settings in code, use the PdfViewer.MarkupToolsSettings property.

The code sample below shows how to specify the default sticky note and text highlight settings:

PdfMarkupToolsSettings markupToolsSettings = pdfViewer.MarkupToolsSettings;
markupToolsSettings.StickyNoteIconName = PdfTextAnnotationIconName.Help;
markupToolsSettings.StickyNoteColor = Color.SkyBlue;

markupToolsSettings.TextHighlightColor = Color.IndianRed;
markupToolsSettings.TextHighlightDefaultSubject = "Spelling";

Edit Annotations

Use the Annotation Properties dialog to change the annotation properties. Right-click the annotation in the document or in the Comments navigation page and select Properties… to invoke this dialog.


Click Set as Default to use the new settings as the default settings for all annotations.

Add Replies and Reviews

The Comments navigation pane shows all document annotations. You can use it to add replies and set review statuses for the annotations.

comments pane

Select an annotation on the pane, enter text in the invoked editor and click Reply to add the reply to the annotation.

add reply

To specify the review status, right-click an annotation, select Set Status, and set the status. Select None to remove the review status.

add review

Remove Annotations

Right-click an annotation in document or in the Comments navigation pane and select Delete in the context menu to remove the annotation. You can also select an annotation and press the Delete key.


Annotation Events

The table below lists events that occur in response to various annotation actions:

Event Description
PdfViewer.AnnotationCreating Fires when the user starts to create an annotation or after the corresponding method call.
PdfViewer.AnnotationCreated Raises after the annotation is created.
PdfViewer.AnnotationGotFocus Occurs when the annotation receives the input focus.
PdfViewer.AnnotationLostFocus Fires when the annotation loses the input focus.
PdfViewer.AnnotationChanged Occurs after the user changed the annotation using the Annotation Properties dialog.
PdfViewer.AnnotationDeleting Occurs before the annotation is deleted.
PdfViewer.AnnotationDeleted Occurs after the annotation is deleted.
PdfViewer.ReplyCreated Occurs after the annotation reply is created in the Comments Panel.
PdfViewer.ReplyChanged Occurs after the annotation reply is changed in the Comments Panel.
PdfViewer.ReplyDeleted Occurs after the annotation reply is deleted in the Comments Panel.