Can no longer modifiying priceset amounts in hooks in 5.1.2

Question

I'm looking for help on adjusting a priceset amount in a hook at the end of a membership signup. Until now under 4.7 for reasons of multi-level priceset complexity I've been adjusting priceset amounts via the hook_civicrm_validateForm by adjusting the values in the $form object. This has been working fine, but this is now longing working in 5.1.2. I realise that strictly speaking I shouldn't modify the $form in the validateForm hook. "The hook is intended for validation rather than altering form values." However I can't see anywhere else to change the amounts. I have two questions, i) Can anyone explain the difference in behaivour between 4.7 and 5.1.2? ii) is there a better place or method to adjust the priceset amount?

Answer 1

You can use Build Amount hook to alter the price. If you want to trigger the change on form submit than you can use $form->_flagSubmitted. This is set to true when form is submitted. You can also use buildform or post process hook. But validateForm is a bad option.

function xxx_civicrm_buildAmount($pageType, &$form, &$amount) {
  if (get_class($form) == 'CRM_Event_Form_Registration_Register' && $form->_flagSubmitted) { 
    foreach ($amount as $key =$value) {
      foreach ($value['options'] as $pid =$value) {
        $amount[$key]['options'][$pid]['amount'] = $value['amount'] - ($value['amount'] * 0.1);
      }
    }
  }
}

HTH

Pradeep