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Remove annotations in ASP.NET Core

27 Apr 20262 minutes to read

Annotations can be removed using the built-in UI or programmatically. This page shows common methods to delete annotations in the viewer.

Delete via UI

A selected annotation can be deleted in three ways:

  • Context menu: right-click the annotation and choose Delete.
    Delete via context menu
  • Annotation toolbar: select the annotation and click the Delete button on the annotation toolbar.
    Delete via annotation toolbar
  • Keyboard: select the annotation and press the Delete key.

Delete programmatically

Annotations can be deleted programmatically either by removing the currently selected annotation or by specifying an annotation id.

<div style="width:100%;height:650px">
  <div style="margin-bottom: 8px;">
    <button onclick="deleteAnnotation()">Delete Annotation</button>
    <button onclick="deleteAnnotationById()">Delete Annotation By ID</button>
  </div>
  <ejs-pdfviewer id="container" style="height:600px" resourceUrl="https://cdn.syncfusion.com/ej2/31.1.23/dist/ej2-pdfviewer-lib" documentPath="https://cdn.syncfusion.com/content/pdf/pdf-succinctly.pdf"></ejs-pdfviewer>
</div>
<script>
window.onload = function() {
  var viewer = document.getElementById('container').ej2_instances[0];
};

function getViewer() { 
  return document.getElementById('container').ej2_instances[0]; 
}

function deleteAnnotation() {
  // Delete the selected annotation
  var viewer = getViewer();
  if (viewer) {
    viewer.annotation.deleteAnnotation();
  }
}

function deleteAnnotationById() {
  var viewer = getViewer();
  // Delete the first annotation using its id from the annotation collection
  if (viewer && viewer.annotationCollection && viewer.annotationCollection.length > 0) {
    viewer.annotation.deleteAnnotationById(viewer.annotationCollection[0].annotationId);
  }
}
</script>

NOTE

Deleting via the API requires the annotation to exist in the current document. Ensure an annotation is selected when using deleteAnnotation(), or pass a valid id to deleteAnnotationById().

View Sample on GitHub

See also