WordPress - remove action defined within plugin class

Whenever $wc_lg = new WC_List_Grid() is instantiated, its going to trigger wp hook. Right after global WP class object is set up, the instance $wg_lg is going to call setup_gridlist() on itself. Its going to trigger woocommerce_before_shop_loop hook. And whenever that happens, again $wg_lg is going to call a function on itself. Namely gridlist_toggle_button().

I want to change the content of the gridlist_toggle_button function

Why not just to change it inside plugin ? Like override everything whats inside it.

global $WC_List_Grid;

How do you know that $WC_List_Grid has its name? Its just a class name. It can be instantiated under any name like $foo or $bar.

I assume that you are coding in functions.php file of your template. Plugins are being loaded before functions.php and remove_action() can only work after add_action() happend.

Important: To remove a hook, the $function_to_remove and $priority arguments must match when the hook was added. This goes for both filters and actions. No warning will be given on removal failure.

http://codex.wordpress.org/Function_Reference/remove_action

So this should actually work just for removing the action, but how that helps you to change content inside of the function? :

remove_action(    'woocommerce_before_shop_loop',    array('WC_List_Grid', 'gridlist_toggle_button'),    30);

Notice that you were using priority 100

EDIT

I found out that do_action('woocommerce_archive_description') happens in archive-product.php and in wc-template-functions.php right before woocommerce_before_shop_loop hook actions are being executed in plugin. Try to use this:

function remove_plugin_actions(){   global $WC_List_Grid;   remove_action( 'woocommerce_before_shop_loop', array( $WC_List_Grid, 'gridlist_toggle_button' ), 30); }add_action('woocommerce_archive_description','remove_plugin_actions');