Add product quantity field limited to the available quantity in Woocommerce shop loop

问题

In Woocommerce, I'm using this code to add the quantity field in woocommerce shop loop:

/**
 * Override loop template and show quantities next to add to cart buttons
 */
add_filter( 'woocommerce_loop_add_to_cart_link', 'quantity_inputs_for_woocommerce_loop_add_to_cart_link', 10, 2 );
function quantity_inputs_for_woocommerce_loop_add_to_cart_link( $html, $product ) {
    if ( $product && $product->is_type( 'simple' ) && $product->is_purchasable() && $product->is_in_stock() && ! $product->is_sold_individually() ) {
        $html = '<form action="' . esc_url( $product->add_to_cart_url() ) . '" class="cart" method="post" enctype="multipart/form-data">';
        $html .= woocommerce_quantity_input( array(), $product, false );
        $html .= '<button type="submit" class="button alt">' . esc_html( $product->add_to_cart_text() ) . '</button>';
        $html .= '</form>';
    }
    return $html;
}

This code working fine, But It doesn't control the available product quantity.

For exemple, if product A has 3 items in stock, in single product page we can only add max 3 items, But in the shop loop with above code, we can enter an unlimited number of items for this product.

How this can be solved?

回答1:

Try the following that will limit product quantity. If the available quantity is 1, the quatity field is hidden. If product is out of stock, the button is disabled displaying "Out of stock":

add_filter( 'woocommerce_loop_add_to_cart_link', 'quantity_inputs_for_woocommerce_loop_add_to_cart_link', 10, 2 );
function quantity_inputs_for_woocommerce_loop_add_to_cart_link( $html, $product ) {
    if ( $product && $product->is_type( 'simple' ) && $product->is_purchasable() && $product->is_in_stock() && ! $product->is_sold_individually() ) {
        $quantity_in_cart = 0;
        if( ! $product->backorders_allowed() && ! WC()->cart->is_empty() ){
            foreach( WC()->cart->get_cart() as $item ){
                if( $item['product_id'] == $product->get_id() ){
                    $quantity_in_cart += $item['quantity'];
                }
            }
        }
        $max_purchase_quantity = $product->get_max_purchase_quantity() - $quantity_in_cart;
        $html = '<form action="' . esc_url( $product->add_to_cart_url() ) . '" class="cart" method="post" enctype="multipart/form-data">';

        if( $product->backorders_allowed() || $max_purchase_quantity > 1 ){
            $html .= woocommerce_quantity_input( array(
                'min_value'   => apply_filters( 'woocommerce_quantity_input_min', $product->get_min_purchase_quantity(), $product ),
                'max_value'   => apply_filters( 'woocommerce_quantity_input_max', $max_purchase_quantity, $product ),
                'input_value' => $product->get_min_purchase_quantity(),
            ), $product, false );
            $html .= '<button type="submit" class="button alt">' . esc_html( $product->add_to_cart_text() ) . '</button>';
        } else {
            $html .= '<a class="button disabled">' . __("Out of stock", "woocommerce") . '</a>';
        }
        $html .= '</form>';
    }
    return $html;
}

Code goes in function.php file of your active child theme (or active theme). Tested and works.

来源：https://stackoverflow.com/questions/53348533/add-product-quantity-field-limited-to-the-available-quantity-in-woocommerce-shop