How do I remove a MassAction from the Product Grid using Observers in Magento?

Question

I want to remove the "Delete" mass action from the Products grid. I am trying to do this from my observer. Here is my observer class

class NameSpace_Module_Model_Observer {

public function isAddProductDeletePermitted($observer) {
    $block = $observer->getBlock();
    if( $block !== null ) {
        if( $block instanceof Mage_Adminhtml_Block_Cms_Block_Grid) {
            $block->getMassactionBlock()->removeItem('delete');
            // echo "DELETE";
        }
    }
    return $this;
}

And here is my config.xml

<?xml version="1.0"?>
<config>

    . . .

    <global>

        . . .

        <events>
            <adminhtml_block_html_before>
                <observers>
                    <is_add_product_form_permitted>
                        <class>Dotlocal_AdvProductGrid_Model_Observer</class>
                        <method>isAddProductDeletePermitted</method>
                    </is_add_product_form_permitted>
                </observers>
            </adminhtml_block_html_before>
        </events>
    </global>
</config>

I cannot seem to get this to work. I am pretty sure this doesn't work because I am trying to removing it before it is added. Then what event should I be observing?

Answer 1

As said in my comment, the type you are checking is wrong.

Two possible solutions.

You get the right grid, which is Mage_Adminhtml_Block_Catalog_Product_Grid and your code become

class Some_Module_Model_Observer
{
    public function isAddProductDeletePermitted ( $observer )
    {
        $block = $observer->getBlock ();
        if ( $block !== null ) {
            if ( $block instanceof Mage_Adminhtml_Block_Catalog_Product_Grid ) {
                $block->getMassactionBlock()->removeItem('delete');
                // echo "DELETE";
            }
        }
        return $this;
    }

}

Or you can also do it on every admin grid (with the generic block Mage_Adminhtml_Block_Widget_Grid) and then verify, with the handle of the page, if you are on the product listing page or not.

Like this :

class Some_Module_Model_Observer
{
    public function isAddProductDeletePermitted ( $observer )
    {
        $block = $observer->getBlock ();
        $layout_handle = Mage::app()->getLayout()->getUpdate()->getHandles();
        if ( $block !== null && $layout_handle[3] == 'adminhtml_catalog_product_index') {
            if ( $block instanceof Mage_Adminhtml_Block_Widget_Grid ) {
                $block->getMassactionBlock()->removeItem('delete');
                // echo "DELETE";
            }
        }
        return $this;
    }

}