How to validate a say coupon code without a picklist

[lpfrnk]

Any ideas on how one would allow a user to input a specific code to allow let's say their ticket to be opened and or updated?  I currently have the field set as text with a Valid If statement tied to a list of valid codes. The key here is that I do not want the dropdown. I want the user to manually input the supplied key and have appsheet validate that code and allow them to do some actions. If the key is not valid nothing should happen or the app should say invalid key.

[dbaum]

For the Valid if property, use an expression that returns Yes/No rather than a list. For example:

IN([_THIS], {expression returning list of coupon codes})

[lpfrnk]

That did the trick with a little tweak.  I encapsulated the IN with an IF statement. Without the if the dropdown remained.

IF(IN([_THIS],coupons[coupon_code]),TRUE,FALSE)

Thanks