Drupal 2 blocks same form function with different output not working

Question

I have dynamically created some blocks depending on how many entries I have in the database:

    function my_module_block_info() {
        $result_set = db_select('my_products', 'products')
            ->fields('products', array('pid', 'name'))
            ->execute();

        $blocks = array();

        foreach($result_set as $product) {
            $blocks['my_product_' . $product->pid] = array(
              'info' => ('My Product ' . $product->name)
            );
        }

        return $blocks;
    }

    function my_module_block_view($delta = '') {
        $pieces = explode('_', $delta);
        $pid = $pieces[2];
        $product = db_select('my_products', 'products')
            ->fields('products')
            ->condition('products.pid', $pid, '=')
            ->execute()
            ->fetchObject();

        $block['subject'] = $product->name;
        $block['content'] = my_module_block_content($product);
        return $block;
    }

function my_module_block_content(&$product) {
    $form = drupal_get_form('my_module_block_form', $product);

    $output = '<p>' . $product->price . '</p>';

    $output .= drupal_render($form);

    return $output;
}

function my_module_block_form($form, &$formstate, $product) {
    $form['submit_product] = array(
      '#type' => 'image_button',
      '#button_type' => 'submit',
      '#src' => base_path() . path_to_theme() . '/images/buy.gif',
    );
    $form['product_name'] = array(
      '#type' => 'hidden',
      '#value' => $product->name,
);
    return $form;
}

My problem is that when I have 2 blocks with different products on one page, the submit function for the second block displayed has the value of $form['product_name']['#value'] equal to the first block, which is an entirely different product. What am I doing wrong?

Answer 1

I would suggest to prefix the form array with your product ID (I guess $product->pid or something like this) :

function my_module_block_form($form, &$formstate, $product) {
    $form[$product->pid]['submit_product] = array(
      '#type' => 'image_button',
      '#button_type' => 'submit',
      '#src' => base_path() . path_to_theme() . '/images/buy.gif',
    );
    $form[$product->pid]['product_name'] = array(
      '#type' => 'hidden',
      '#value' => $product->name,
    );
    return $form;
}

Then the fields shouldn't be overwritten.

Answer 2

I found a solution here: Multiple forms on single page?. The problem is drupal assigns the same id to forms because they are using the same function. To overide the id, simply call to a function that ddosen't exist and have a simple hook_form redirect it like so:

function my_module_forms($form_id, $args) {
    $forms = array();

    if(substr($form_id, 0, 10) == 'my_module_') {
        $forms[$form_id] = array(
          'callback' => 'my_module_block_form',
        );
    }

    return $forms;
}