Valid If - default system error

[Mike_T]

I’m using a QR code scanner. When I set the valid if formula to:
(IN([_THIS], QR Codes[QR_Code]))
and I scan a QR code that is valid and On the list, it works fine. When I scan a code NOT on the list I get the default system error “The scan result didn’t match any known entries”.

When I add a NOT(…) around the above formula the results are reversed and the error message is the one I input into the invalid value error field.

How do I get my custom error message to appear in the correct scenario above?

[Steve]

[Mike_T]

Yep. I have both fields filled out but still get the default error message unless I use the NOT( ) formula. I guess I could try NOT(NOT(…)) to see if it would trigger.

I think I’ll just change the values in the Localized section. This pops up the error on screen which looks better.

[Steve]

Please post a screenshot of the error screen, and a screenshot of the column configuration screen.

[Mike_T]

I’m ok with just using the localized message to show the error. However, I just noticed a behavior that I need to limit.

Is there a way to force the user to only use the QR scanner to input into the field? I would still like to use the valid if: (IN([_THIS], QR Codes[QR_Code])) But I don’t want the user to be able to tap the field and select from the drop down list. btw the QRCode field is Type: Text, if this matters.

[Steve · Accepted solution]

Mike_T:

I don’t want the user to be able to tap the field and select from the drop down list.

Wrap your existing Valid If expression with:

AND(..., TRUE)

or:

OR(..., FALSE)

[Mike_T]

Steve:

AND(..., TRUE)

Works perfect! Thanks for all you do!

[atyka]

@Mike_T @Steve 

Did you solve the problem ?

I try in many way but without succes... you can see my other post 

https://www.googlecloudcommunity.com/gc/AppSheet-Q-A/QR-Code-Valid-if/td-p/444626