Validation of rule on button submit should not start the process when evaluated to be false

Question

We have a requirement where a rule has to be evaluated which has to happen at a button click and we have 3 buttons which needs this rule to be evaluated wrapped in a cardlayout. 
 Now the do we have any mechanism to evaluate the rule when any button is clicked and throw a error message when rule is not evaluated as true. Please note that all the buttons have processes in them and we should not execute the process when the rule is false. 
 Thanks in advance!!!

Mike Schmitt · Answer

Please look into the slightly lesser-known a!validationMessage() component, as I've been able to successfully use it when I've had use cases that sound similar to yours. Namely, it allows you to throw section-level or form-level validation that validates when any submit button is clicked.

Mike Schmitt · Answer

I take that back - I forgot that the saveInto() of a button click doesn't execute until validations pass, so my suggestion above never quite works out. 
 Does the user interact with the form at all before clicking any of the submit buttons/links? If you put your validation rule in a with() variable or (preferably) an a!refreshVariable variable with "refreshAlways" set to TRUE (as suggested previously by the other commentor), then any time a user interacts with the form prior to clicking the submission button/link will re-try the validation logic. 
 If not, I'm afraid you might need to compromise and use some sort of 2-click submit functionality, like having one button/link that forces the validation to re-run and save the result locally, and only after that's done (and the validation passes) you allow the Submit buttons/links to actually submit the form.