所以我改用了这个钩子:

So I've used this hook instead:

woocommerce_ajax_added_order_items

然后在函数中:

foreach ( $order->get_items() as $order_item_id => $order_item_data ) {
    //    Set custom price.
}

似乎可以正常工作.

事实证明，如果您想一次添加多个项目，上述挂钩只会获取最后一个项目.

It turns out that the above hook only get the last item in case you want to add multiple items at once.

仅在循环中对通过ajax添加的项目(不影响现有项目)执行的更好的钩子是:

A better hook which is executed in the loop ONLY for the items added via ajax (not affecting the existing ones) is:

woocommerce_ajax_add_order_item_meta

woocommerce_ajax_add_order_item_meta

然后在循环中，您可以对购物车中的商品进行循环，如果购物车ID匹配，则可以更改产品.

Then in the loop you can do a loop over the items in the cart and if the cart id matches, you can change the product.

function update_order_prices_on_admin_ajax( $item_id, $item, $order )
    foreach ( $order->get_items() as $order_item_id => $order_item_data ) {
        if ( $order_item_id == $item_id ) {
            // Do changes here.

            // Runs this after making a change to $order_item_data
            $order->apply_changes();
            $order->save();
        }
    }
}
add_action( 'woocommerce_ajax_add_order_item_meta', 'update_order_prices_on_admin_ajax', 99, 3 );