I'm creating a custom plugin for my website.

In some part of this plugin I need to store extra meta in `wp_postmeta` for each orders.

I added this in my plugin's class:

```
add_action ('woocommerce_before_checkout_process', array( &$this, 'add_item_meta', 10, 2) );

```

And this is `add_item_meta()` function:

```
function add_item_meta( $item_id, $values ) {
  wc_add_order_item_meta($item_id, '_has_event', 'yes' );
}

```

This function is not complete, but nothing happens with this codes; I think I need to use another hook but I can't find a proper one.

Does anyone know anything about this?

I also have another problem with `$item_id`: this is woocommerce global variable but I can't see it in my plugin!

I mean I don't have access to this variable from my plugin or something like this!