Upload in Form

Embed the uploader inside an HTML form alongside other fields. Upload files as part of a larger form submission.

What you should see: the uploader inside a normal form. Files transfer out of band and their identifiers are submitted with the rest of the fields on post.

<form method="post">
 <div>
 <label for="title">Title</label>
 <input type="text" id="title" name="title" />
 </div>

 <div>
 <label>Attachments</label>
 <core-upload asp-upload-url="/api/upload/upload"
 asp-multiple="true"
 asp-progress="true">
 </core-upload>
 </div>

 <button type="submit">Submit Form</button>
</form>

References instead of bytes

The uploader transfers in the background and the completed file identifiers go into a hidden input, so the form posts a short list rather than any file content. Submitting stays instant no matter how much was uploaded.

Guard the submit button

Nothing stops a user submitting mid-upload, and the form would then post an incomplete list. Disable submit until the queue is idle, or check the state in the handler — a record saved without an attachment the user believed they added is discovered much later, usually by someone else.