"Order Id", ); public $display_name = 'Order standard'; public function getValue($post, $field) { $order = isset($post->orderId) ? get_post($post->orderId) : $post; return isset($order->{$field}) ? $order->{$field} : ''; } public function getName($field) { return isset($this->fieldNames[$field['value']]) ? $this->fieldNames[$field['value']] : ''; } }