Question

So far I’ve just found out that I could write an own view helper but as I’m new to the framework I don’t know how to do that. I hope there’s a simpler way!?

Answer 1

I was just about to ask this question myself with my own solution, to provide for the community, so to speak, when I saw you question pop up in the suggestions.

My simple and pretty elegant solution, if I say so myself, uses a simple custom decorator. It does nothing to the content it receives, but it alters the element.

class App_Form_Decorator_ErrorClass
    extends Zend_Form_Decorator_Abstract
{

    protected $_placement = null;

    protected $_options = array(
        'class' => 'error'
    );

    public function render( $content )
    {
        $element = $this->getElement();

        if( $element->hasErrors() )
        {
            $errorClass = $this->getOption( 'class' );
            $currentClass = $element->getAttrib( 'class' );
            $element->setAttrib( 'class', ( !empty( $currentClass ) ? $currentClass . ' ' . $errorClass : $errorClass ) );
        }

        return $content;
    }
}

Usage:
All you need to do is add the decorator before the ViewHelper decorator, and your set.

public function init()
{
    $elementDecorators = array(
        'ErrorClass',
        'ViewHelper',
        // etc..
    );

    // or:
    $elementDecorators = array(
        array(
            'ErrorClass',
            array( 'class' => 'custom-class' ) // defaults to 'error'
        ),
        'ViewHelper',
        // etc..
    );

    // then just add the decorators to an element the way you usually do, for instance like so:
    $someElement = new Zend_Form_Element_Text( 'someElement' );
    $someElement->setDecorators( $elementDecorators );

    // etc...

O, PS.: Be sure to add the correct prefix path in your form:

$this->addPrefixPath( 'App_Form', 'App/Form' ); // or your own namespace