Updating the Layout from the Observer

Question

I am workin on a slider block Magento, and I am trying to genreate and update my Layout from the Observer :

Event: controller_action_layout_load_before

This my Observer Method :

        $myXml="<".$page.">";
    $myXml.='<reference name="'.$posH.'">';
    $myXml.='<block type="sliderboard/slider" name="sliderboard" '.$posV.'="-" template="sliderboard/myview.phtml"/>';
    $myXml.='</reference>';
    $myXml.="</".$page.">";

    $layout = $observer->getEvent()->getLayout();
    //$layout=Mage::getSingleton('core/layout');
    //Zend_Debug::dump($myXml); die();          
    $layout->getUpdate()->addUpdate($myXml);
    $layout->getUpdate()->load();
    $layout->generateXml();
    $layout->generateBlocks();

the fact is, this is what i get from the "$myXML" variable :

<cms_page>
<reference name="content">
<block type="sliderboard/slider" name="sliderboard" after="-" template="sliderboard/myview.phtml"/>
</reference>
</cms_page>

And It doesn't work !! but whene I have tried to copy/past this xml in my layout it works ! the Xml code is correct! I Need Help
Thanks !

Answer 1

$layout->getUpdate()->addUpdate($myXml);

addUpdate() don't work with "Actions" so we can only put this part of the layout :

<reference name="content">
<block type="myblock/block" name="sliderboard" after="-" template="mytemp/tmplate.phtml"/>
</reference>

And to choose between (cms, category and product) we use :

$action = $observer->getEvent()->getAction();
$fullActionName = $action->getFullActionName();

We compare $fullActionName to : cms_index_index / catalog_category_view /catalog_product_view

And if it equal tu what we need we contunu to :

$page="cms_index_index";    
switch ($slider->getSldPage()){

    case 'product':  $page="catalog_product_view";  
        break;
    case 'category': $page="catalog_category_view";         
        break;
}

$myXml.='<reference name="'.$posH.'">';
$myXml.='<block type="sliderboard/slider" name="sliderboard" '.$posV.'="-" template="sliderboard/myview.phtml"/>';
$myXml.='</reference>';

$action = $observer->getEvent()->getAction();
$fullActionName = $action->getFullActionName();
$layout = $observer->getEvent()->getLayout();

if ($fullActionName==$page)
{
    $layout->getUpdate()->addUpdate($myXml);
    $layout->generateXml();         
}

Hope this will help:)

Now I'm trying to choose what category and what product I'll display in, if you have an idea.