I have a Powerapps app that we're using at a tech support bar to check people in as they walk up. This particular screen is pretty simple: they type their name in the "Requester" field, which is tied to a SharePoint list Person column. It looks up their name, and they can select it and submit (see attachment).
I have another screen that watches the backing SharePoint list and populates a gallery with the names in the list (it's basically the queue). When someone taps their name in the lookup and submits, it shows up fine in the queue. Here's the issue I'm running into: if someone types their name in, but fails to select their name from the lookup and submits as-is, a blank is stored in the SharePoint list instead of their name.
Is there a way that I can validate that field before they submit? I know there are validation techniques in Powerapps, but I'm not sure exactly how to validate that a proper Person was selected before they submit.