Is there a way to do a check before submitting a form?

[Jeff_Hager]

You can if you create a custom form and use a relation to check for an existing barcode. Only enable the submit button if the relation is empty.

How do I create a custom form?

I’m just dropping this here so I have something to refer people to when they ask. This is a simple concept app (copyable), that demonstrates the following techniques: Building custom forms for adding and editing list items (as an alternative to the native forms provided by Glide) Preventing duplicate new entries using User Specific Columns and Relations Enforcing mandatory input items The use of visibility conditions and user specific booleans to control user flow There is nothing particula…