How to get order items ids to get some product meta data?

2018 Update:

• Clarifying the answer with 2 possible cases
• Added compatibility for woocommerce 3+

So There can be 2 cases:

1) Get product meta data (not set in order item meta data):

You will need to get the product ID in the foreach loop for a WC_Order and to get some metadata for this product you wil use get_post_meta() function ( but NOT wc_get_order_item_meta() ).

So here is your code:

global $post;$order = wc_get_order( $post->ID );$items = $order->get_items(); foreach ( $order->get_items() => $item ) {    // Compatibility for woocommerce 3+    $product_id = version_compare( WC_VERSION, '3.0', '<' ) ? $item['product_id'] : $item->get_product_id();    // Here you get your data    $custom_field = get_post_meta( $product_id, '_tmcartepo_data', true);     // To test data output (uncomment the line below)    // print_r($custom_field);    // If it is an array of values    if( is_array( $custom_field ) ){        echo implode( '<br>', $custom_field ); // one value displayed by line     }     // just one value (a string)    else {        echo $custom_field;    }}

2) Get order item meta data (custom field value):

global $post;$order = wc_get_order( $post->ID );$items = $order->get_items(); foreach ( $order->get_items() as $item_id => $item ) {    // Here you get your data    $custom_field = wc_get_order_item_meta( $item_id, '_tmcartepo_data', true );     // To test data output (uncomment the line below)    // print_r($custom_field);    // If it is an array of values    if( is_array( $custom_field ) ){        echo implode( '<br>', $custom_field ); // one value displayed by line     }     // just one value (a string)    else {        echo $custom_field;    }}

If the custom field data is an array, you can access the data in a foreach loop:

// Iterating in an array of keys/valuesforeach( $custom_field as $key => $value ){    echo '<p>key: '.$key.' | value: '.$value.'</p>';} 

All code is tested and works.

Reference related to data in orders:

• How to get WooCommerce order details (also for woocommerce 3)
• Get Order items and WC_Order_Item_Product in Woocommerce 3

When doing the foreach on $order->get_items(), their key is actually the orderline ID. So:

foreach ( $order->get_items() as $key => $item ) {    $data = wc_get_order_item_meta( $key, '_tmcartepo_data' );    ...}

Late to the party, but being working with the same point with TM Extra Product Options plugin, I think this is what answers your question:

$order = wc_get_order( $post->ID );$items = $order->get_items();foreach( $items as $item ){    $data = unserialize($item['item_meta']['_tmcartepo_data'][0]);    $a = $data[0]['value'];    $b = $data[1]['value'];    echo $a;    echo $b;}

Tested and works in my case.