Unload PDF documents programmatically in ASP.NET Core PDF Viewer

28 Feb 20262 minutes to read

Clear the current PDF document and release associated resources by calling the unload() method. This resets the viewer UI and is useful when switching between documents or clearing sensitive content after review.

Follow these steps to unload a PDF document programmatically:

Step 1: Follow the ASP.NET Core PDF Viewer getting started guide to set up the required scripts, styles, and controller configuration.

Step 2: Add a button and script to call the unload() method. Place the script in your Razor page after the viewer element:

<button type="button" onclick="unload()">Unload Document</button>

<div style="width:100%;height:600px">
    <ejs-pdfviewer
        id="pdfviewer"
        documentPath="https://cdn.syncfusion.com/content/pdf/pdf-succinctly.pdf">
    </ejs-pdfviewer>
</div>

<script>
    // Unload the PDF document.
    function unload() {
        var viewer = document.getElementById('pdfviewer').ej2_instances[0];
        viewer.unload();
    }
</script>
<button type="button" onclick="unload()">Unload Document</button>

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

<script>
    // Unload the PDF document.
    function unload() {
        var viewer = document.getElementById('pdfviewer').ej2_instances[0];
        viewer.unload();
    }
</script>

After calling unload(), the viewer clears the document, toolbar state, and cached data until a new PDF is loaded. This pattern works identically in both standalone and server-backed configurations, ensuring clean state management before loading different documents.

View sample on GitHub