signatureSelect and signatureUnselect events

The Syncfusion® ASP.NET Core PDF Viewer raises the signatureSelect and signatureUnselect events whenever a handwritten signature annotation gains or loses focus. Use these callbacks to log reviewer actions, update guidance in the surrounding UI, or validate that a signer completes required steps before saving a document.

signatureSelect

This event fires when the user taps or clicks an existing handwritten signature or finishes drawing a new one. The event argument includes metadata such as the annotation ID, bounds, and page number so that applications can highlight related UI elements or load signer details.

signatureUnselect

This event fires after the focus moves away from a signature or the user deselects it. Handle the callback to persist edits, disable context commands, or reset state that should only be active while a signature is selected.

Follow these steps to wire the events in an ASP.NET Core application:

  1. Create a PDF Viewer sample by following the ASP.NET Core getting started guide. The guide explains how to register the viewer scripts, styles, and controller endpoints.
  2. Place the buttons and script inside the Razor page so the handlers attach after the viewer initializes. The console output appears in the browser developer tools and can be replaced with custom UI updates or service calls.

The following sample subscribes to both events in standalone and server-backed configurations.

@{
    ViewData["Title"] = "Home page";
}

<div style="width:100%;height:600px">
    <ejs-pdfviewer id="pdfviewer"
                   documentPath="https://cdn.syncfusion.com/content/pdf/pdf-succinctly.pdf"
                   resourceUrl="https://cdn.syncfusion.com/ej2/23.2.6/dist/ej2-pdfviewer-lib"
                   signatureSelect="signatureSelect"
                   signatureUnselect="signatureUnselect">
    </ejs-pdfviewer>
</div>
<script type="text/javascript">

    function signatureSelect(args) {
        console.log('Signature selected:', args);
    }
    function signatureUnselect(args) {
        console.log('Signature selected:', args);
    };

</script>
@{
    ViewData["Title"] = "Home page";
}

<div style="width:100%;height:600px">
    <ejs-pdfviewer id="pdfviewer"
                   documentPath="https://cdn.syncfusion.com/content/pdf/pdf-succinctly.pdf"
                   serviceUrl="/Index"
                   signatureSelect="signatureSelect"
                   signatureUnselect="signatureUnselect">
    </ejs-pdfviewer>
</div>
<script type="text/javascript">

    function signatureSelect(args) {
        console.log('Signature selected:', args);
    }
    function signatureUnselect(args) {
        console.log('Signature selected:', args);
    };

</script>

By handling signatureSelect and signatureUnselect, applications can audit signer activity, enable or disable toolbar actions, and provide immediate feedback when signatures change state.