Get the raw field value.
$index: The index count of the row.
$field: The id of the field.
function get_field_value($index, $field) {
$this->view->row_index = $index;
$value = $this->view->field[$field]
->get_value($this->view->result[$index]);
unset($this->view->row_index);
return $value;
}