Question

I’m creating a module that allows the user to choose the website during creating a role permission (System -> Permission -> Role -> Add New role -> Role Resource). I’m using an observer to achieve this, however I cannot get the form object.

Observer.php

class Mymodule_Mycompany_Model_Observer 
{ 
    public function appendCustomRow(Varien_Event_Observer $observer)
    {
        $block = $observer->getEvent()->getBlock();
        if (!isset($block)) {
            return $this;
        }
        if ($block->getType() == 'adminhtml/permissions_editroles') {       
            //get form instance
            $form = $observer->getEvent()->getForm();
            //create new custom fieldset 'website'
            $fieldset = $form->addFieldset('website', array(
                'legend' => 'Website Extras',
                'class' => 'fieldset-wide'
                )
            );
            //add new field
            $fieldset->addField('website', 'text', array(
                'name'      => 'website',
                'label'     => Mage::helper('adminhtml')->__('Website'),
                'title'     => Mage::helper('adminhtml')->__('Website'),
                'disabled'  => false,
            ));
        }
    }
}

Mymodule/Mycompany/etc/config.xml

<adminhtml>
         <events>
            <core_block_abstract_prepare_layout_before>
                <observers>
                    <Event_column_append>
                        <type>model</type>
                        <class>Mymodule_Mycompany_Model_Observer</class>
                        <method>appendCustomColumn</method>
                    </Event_column_append>
                </observers>
            </core_block_abstract_prepare_layout_before>
          </events>
</adminhtml>

Answer 1

I worked it out. Here is the modified piece of code that works

public function appendCustomColumn(Varien_Event_Observer $observer)
{
    $block = $observer->getEvent()->getBlock();
    if (!isset($block)) {
        return $this;
    }
    if ($block->getType() == 'adminhtml/permissions_tab_roleinfo') {       
        //get form instance
        $form = $block->getForm();
        //create new custom fieldset 'website'
        $fieldset = $form->addFieldset(
            'website_field', 
            array(
                'legend' => 'Website Extras',
                'class' => 'fieldset-wide'
            )
        );
        //add new field
        $fieldset->addField('website', 'text', array(
            'name'      => 'website',
            'label'     => Mage::helper('adminhtml')->__('Website'),
            'title'     => Mage::helper('adminhtml')->__('Website'),
            'disabled'  => false,
        ));
    }
}

XML Configuration:

<events>
    <adminhtml_block_html_before>
        <observers>
            <Event_column_append>
                <type>model</type>
                <class>Mymodule_Mycompany_Model_Observer</class>
                <method>appendCustomColumn</method>
            </Event_column_append>
        </observers>
    </adminhtml_block_html_before>
</events>

1. You need to use the event ‘adminhtml_block_html_before’ as the event which you were using did not even create the form object. That is why you were nt able to access the form object.
2. The block that is creating this form elements was ‘adminhtml/permissions_tab_roleinfo’.
3. The method you were using was the not same one in the observer.

Hope that helps :)…

Cheers,
Swapna