validation problem

[eluser]Michael Wales[/eluser]
My first thought, with a <select> input is... don't put -1 within the <option>s - but, just to answer your question.

Code:

function form() {
  $this->load->library('validation');
  $this->validation->set_rules(array(
    'selectbox' => 'required|callback__check_setbox'));
  $this->validation->set_fields(array(
    'selectbox' => 'Your select box'));
}

function _check_setbox($val) {
  if ((int) $val >= 0) {
    return TRUE;
  }
  $this->validation->set_message('_check_setbox', 'Your setbox must be greater than -1.');
  return FALSE;
}