layout: post

title: How to lock an annotation in WPF pdf viewer | Syncfusion

description: Learn about how to enable or disable lock option for an annotation programmatically or UI using WPF Pdf Viewer.

platform: wpf

control: PDF Viewer

documentation: ug

The WPF PDF Viewer provides a support to enable or disable lock option for the annotation in a pdf document. When an annotation is locked, it cannot be moved, resized, and removed.

The annotation can be locked either by default settings or by annotation changed events using the `IsLocked` API.

To lock an annotation, set the `IsLocked` value in annotation settings as true. The following code sample illustrates how to lock all annotations by default.

{% tabs %}

{% highlight C# %}

private void Window_Loaded(object sender, RoutedEventArgs e)

{

PdfLoadedDocument pdf = new PdfLoadedDocument("Input.pdf");

//Loads the PDF document

pdfviewer.Load(pdf);

//Sets the value to lock all annotations

pdfviewer.PolygonAnnotationSettings.IsLocked = true;

pdfviewer.PolylineAnnotationSettings.IsLocked = true;

pdfviewer.CircleAnnotationSettings.IsLocked = true;

pdfviewer.RectangleAnnotationSettings.IsLocked = true;

pdfviewer.LineAnnotationSettings.IsLocked = true;

pdfviewer.ArrowAnnotationSettings.IsLocked = true;

pdfviewer.StickyNoteAnnotationSettings.IsLocked = true;

pdfviewer.StampAnnotationSettings.IsLocked = true;

pdfviewer.InkAnnotationSettings.IsLocked = true;

pdfviewer.FreeTextAnnotationSettings.IsLocked = true;

pdfviewer.HighlightAnnotationSettings.IsLocked = true;

pdfviewer.UnderlineAnnotationSettings.IsLocked = true;

pdfviewer.StrikethroughAnnotationSettings.IsLocked = true;

}

{% endhighlight %}

{% endtabs %}

To lock an annotation by annotation changed event, set the value of `IsLocked` in the annotation changed event as true. The following code sample illustrates how to lock sticky note annotation by using the annotation changed event while adding an annotation.

{% tabs %}

{% highlight C# %}

//Wires the event handler for ` StickyNoteAnnotationChanged` event

pdfviewer.StickyNoteAnnotationChanged += Pdfviewer_StickyNoteAnnotationChanged;

private void Pdfviewer_StickyNoteAnnotationChanged(object sender, StickyNoteAnnotationChangedEventArgs e)

{

if (e.Action == AnnotationChangedAction.Add)

{

//Sets the value to lock the annotation

e.Settings.IsLocked = true;

}

}

{% endhighlight %}

{% endtabs %}

N> Similarly, you can implement it for all other annotations in code behind.

The check box control labeled as “Locked” will appear in the annotation properties window, allowing us to enable or disable lock option for the selected annotation.

The following image shows how to enable lock option for sticky note annotation in UI.


N> Similarly, you can set it for all other annotations in UI.