Hello @Raph,
I currently have a similar need to validate a user entry with an arbitrary restriction such as duplication. What you could do is do the validation within the spreadsheet and once validated let the user “push” the validated username to the username field.
Unfortunately this would generally rule out using a form, as form values are not written to the spreadsheet until submitted and only write to new rows. However, what you could do is have a 2 step process:
- User opens Change Username Page and is presented with a “Validate New Username” form button
- User clicks the button and the form opens. The user enters their desired username into the only text field and hits submit
- Their New Username is then logged in the “Username Request” sheet
- An Excel formula then populates a few fields in the users ownered row (Latest New Name, Valid status)
- User is automatically returned to Change Username Page (normal for forms)
- Seconds later a component appears with the results of their validation a yes or a no and their chosen name
- If yes, another new field will also be available: a choice component with only one possible value: the recently validated name (visibility based on the valid status)
- The user now clicks the choice component and selects their validated name, which moves the validated name into the name column
Let me know if you would like more details as I have built and tested the above.
Good luck!
