Codeigniter HMVC回调函数未在ajax表单验证中显示错误

Question

我有一个带回调函数的表单验证函数，它工作正常，直到我把ajax放在它上面。唯一的问题是，如果错误来自回调函数

，它不会显示错误

这是我的控制器

public function create(){

    $data = array('success' => false, 'messages' => array());

    $this->form_validation->set_rules('DEPARTMENT','Department','trim|required|max_length[50]|callback_if_exist');

    $this->form_validation->set_error_delimiters('<p class="text-danger"','</p>');

    if($this->form_validation->run($this)){

        $insert = $this->Department_Model->insert();
        $data['success'] = true;
    }else{
        foreach ($_POST as $key => $value) {
            # code...
            $data['messages'][$key] = form_error($key);
        }
    }

    echo json_encode($data);
}

/////////// CALLBACK

public function if_exist(){

    $available = $this->Department_Model->check_if_exist();

    if($available){
        return TRUE;
    }else{

        $this->form_validation->set_message('if_exist','{field} already exist!');
        return FALSE;

    }

}

模型

public function check_if_exist(){

    $sql = "SELECT * FROM $this->table WHERE DEPARTMENT = ?";
    $data = array('DEPARTMENT' => $this->input->post('DEPARTMENT'));

    $query = $this->db->query($sql, $data);

    if($query->num_rows() == 0){

        return TRUE;
    }else{

        return FALSE;
    }

这是我的java脚本

<script>
  $('#form-user').submit(function(e) {
    e.preventDefault();

    var me = $(this);

    // perform ajax
    $.ajax({
      url: me.attr('action'),
      type: 'post',
      data: me.serialize(),
      dataType: 'json',
      success: function(response) {
        if (response.success == true) {
          // if success we would show message
          // and also remove the error class
          $('#the-message').append('<div class="alert alert-success">' +
            '<span class="glyphicon glyphicon-ok"></span>' +
            ' Data has been saved' +
            '</div>');
          $('.form-group').removeClass('has-error')
                  .removeClass('has-success');
          $('.text-danger').remove();

          // reset the form
          me[0].reset();

          // close the message after seconds
          $('.alert-success').delay(500).show(10, function() {
            $(this).delay(3000).hide(10, function() {
              $(this).remove();
            });
          })
        }
        else {
          $.each(response.messages, function(key, value) {
            var element = $('#' + key);

            element.closest('div.form-control')
            .removeClass('has-error')
            .addClass(value.length > 0 ? 'has-error' : '')
            .find('.text-danger')
            .remove();

            element.after(value);
          });
        }
      }
    });
  });
</script>

它显示除回调错误

之外的每个错误