Restrict contacts available to be assigned to an activity

Question

We're looking to restrict the contacts that are available when assigning an activity. Has anyone done this before?

The email function is really useful, but due to the sensitive nature of some of the information, we want to remove the possibility of human error as someone could accidentally choose the wrong contact to assign.

It would be great if this could be restricted by group the same was a custom contact reference field can be done.

Answer 1

The EntityRef field on the form can be given that restriction. Best way to do it is probably via a hook, e.g.

hook_civicrm_preProcess($formName, &$form) {
  if (is_a($form, 'CRM_Activity_Form_Activity')) {
    $form->_fields['assignee_contact_id']['attributes']['api']['params']['group'] = 1;
  }
}

(where "hook" is the name of your module and "1" is the id of the group)

Note use of is_a rather than the $formName so we also catch the case activity form.