Get Order items and WC_Order_Item_Product in WooCommerce 3

If you use the get_id() method, you get your item ID which is 15 in your code.

Get the product ID:
The correct WC_Order_Item_Product method to get the Product Id is: get_product_id()

Get the variation ID:
The correct WC_Order_Item_Product method to get the variation Id is: get_variation_id()

Get the order ID
The correct WC_Order_Item_Product method to get the Order Id is: get_order_id()

Get the WC_Product object
The correct WC_Order_Item_Product method to get WC_Product object is:get_product()

Get the WC_Order object
The correct WC_Order_Item_Product method to get WC_order object is:get_order()

Get and unprotecting the data and meta data using WC_Data methods:

• get_data()
  
• get_meta_data()

Get The WC_Product object from the order item ID:

$order_item_id = 15;$item = new WC_Order_Item_Product($order_item_id);// The product ID$product_id = $item->get_product_id(); // The variation ID$variation_id = $item->get_variation_id(); // The WC_Product object$product = $item->get_product(); // The quantity$quantity = $item->get_quantity(); // The order ID$order_id = $item->get_order_id(); // The WC_Order object$order = $item->get_order(); // The item ID$item_id = $item->get_id(); // which is your $order_item_id// The product name$product_name = $item->get_name(); // … OR: $product->get_name();// Get the product SKU (using WC_Product method)$sku = $product->get_sku();// Get line item totals (non discounted)$total     = $item->get_subtotal(); // Total without tax (non discounted)$total_tax = $item->get_subtotal_tax(); // Total tax (non discounted)// Get line item totals (discounted when a coupon is applied)$total     = $item->get_total(); // Total without tax (discounted)$total_tax = $item->get_total_tax(); // Total tax (discounted)

Get the order items from the WC_Order object (and use the WC_product Object):

$order_id = 156; // The order_id// get an instance of the WC_Order object$order = wc_get_order( $order_id );// The loop to get the order items which are WC_Order_Item_Product objects since WC 3+foreach( $order->get_items() as $item_id => $item ){    //Get the product ID    $product_id = $item->get_product_id();    //Get the variation ID    $variation_id = $item->get_variation_id();    //Get the WC_Product object    $product = $item->get_product();    // The quantity    $quantity = $item->get_quantity();    // The product name    $product_name = $item->get_name(); // … OR: $product->get_name();    //Get the product SKU (using WC_Product method)    $sku = $product->get_sku();    // Get line item totals (non discounted)    $total     = $item->get_subtotal(); // Total without tax (non discounted)    $total_tax = $item->get_subtotal_tax(); // Total tax (non discounted)        // Get line item totals (discounted when a coupon is applied)    $total     = $item->get_total(); // Total without tax (discounted)    $total_tax = $item->get_total_tax(); // Total tax (discounted)}

###Accessing data and custom meta data:

1). Unprotecting WC_Order_Item_Product data and custom meta data:

You can use all WC_Order_Item_Product data methods or you can unprotect the data using WC_Data following methods:

$order_id = 156; // The order_id// get an instance of the WC_Order object$order = wc_get_order( $order_id );// The loop to get the order items which are WC_Order_Item_Product objects since WC 3+foreach( $order->get_items() as $item_id => $item ){    // Get the common data in an array:     $item_product_data_array = $item->get_data();    // Get the special meta data in an array:     $item_product_meta_data_array = $item->get_meta_data();    // Get the specific meta data from a meta_key:     $meta_value = $item->get_meta( 'custom_meta_key', true );    // Get all additional meta data (formatted in an unprotected array)    $formatted_meta_data = $item->get_formatted_meta_data( ' ', true );    // Get line item totals (non discounted)    $total     = $item->get_subtotal(); // Total without tax (non discounted)    $total_tax = $item->get_subtotal_tax(); // Total tax (non discounted)        // Get line item totals (discounted when a coupon is applied)    $total     = $item->get_total(); // Total without tax (discounted)    $total_tax = $item->get_total_tax(); // Total tax (discounted)}

2). The Array Access is still possible (for backwards compatibility with legacy arrays) to get the common data directly:

$order_id = 156; // The order_id// get an instance of the WC_Order object$order = wc_get_order( $order_id );// The loop to get the order items which are WC_Order_Item_Product objects since WC 3+foreach( $order->get_items() as $item_id => $item ){        $product_id    = $item['product_id']; // Get the product ID    $variation_id  = $item['variation_id']; // Get the variation ID    $product_name  = $item['name']; // The product name    $item_qty      = $item['quantity']; // The quantity    // Get line item totals (non discounted)    $line_total     = $item['subtotal']; // or $item['line_subtotal'] -- The line item non discounted total    $line_total_tax = $item['subtotal_tax']; // or $item['line_subtotal_tax'] -- The line item non discounted tax total    // Get line item totals (discounted)    $line_total2     = $item['total']; // or $item['line_total'] -- The line item non discounted total    $line_total_tax2 = $item['total_tax']; // The line item non discounted tax total    // And so on ……}

As reference:

• Get the metadata of an order item in woocommerce 3
• How to get WooCommerce order details

WC_Order_Item_Product inherits from WC_Order_Item, which has get_order_id(), so you can get the Order ID with

$order_item->get_order_id();