If I have a few views, add.ctp, edit.ctp all using the same code for the form.
I have created another view file called _form.ctp
For displaing same part we call $this->renderPartial(’_form’);

How I implement it?

All we need is overload View class with renderPartial function implementation. The goal of function is call renderElement with correct path to view.

<?php
class ExtView extends View 
{    

    function renderPartial($name, $params = array(), $loadHelpers = false) {
        if ((strpos($name, ‘\\’)===false) && (strpos($name, ‘/’)===false)) {
            $name = ‘..’ . DS . Inflector::underscore($this->name) . DS . $name;            
        }
        return $this->renderElement($name, $params, $loadHelpers);
    }

    
}
?>

Now in app_controller all I need is set default view class in beforeRender callback:

<?php
class AppController extends Controller {
   
    function beforeRender() {
        $this->view=‘Ext’;
        return true;
    }    
    
}
?>