title: WooCommerce - Get order cart items quantity ADMIN
body: <p>This variable works for the template: </p>
  
  <pre><code>$woocommerce-&gt;cart-&gt;cart_contents_count;
  </code></pre>
  
  <p>But doesn't work for admin...</p>
  
  <p>Does anyone know how to get the cart items quantity and display it on the order edition page?</p>
  
  <hr>
  
  <pre><code>/**
  * Display field value on the order edition page
  **/
  add_action( 'woocommerce_admin_order_data_after_billing_address','my_custom_checkout_field_display_admin_order_meta', 10, 1 );
  
  function my_custom_checkout_field_display_admin_order_meta($order){
   // doesn't work...
   echo $woocommerce-&gt;cart-&gt;cart_contents_count;
  }
  </code></pre>
  
  <p>}</p>