//VIEW
<?php
$this->breadcrumbs=array(
    'Invoices'=>array('index'),
    'Manage',
);

$this->menu=array(
    array('label'=>'List Invoice', 'url'=>array('index')),
    array('label'=>'Create Invoice', 'url'=>array('create')),
);

$form=$this->beginWidget('CActiveForm', array(
    'id'=>'invoice-form',
    'enableAjaxValidation'=>false,
));
$this->widget('zii.widgets.grid.CGridView', array(
    'id'=>'invoice-grid',

    'dataProvider'=>$model->search(),

        'filter'=>$model,
    'columns'=>array(
                array(
                    'name'=>'contactName',
                    'value'=>'$data->user->contact->name',
                    //'filter'=>CHtml::activeTextField(Contact::model(), 'name')
                ),
                array(
                    'name'=>'contactEmail',
                    'value'=>'$data->user->contact->email',
                    //'filter'=>CHtml::activeTextField(Contact::model(), 'email')
                ),
                array(
                    'name'=>'bandwidth',
                    'value'=>'number_format($data->bandwidth, 2)',
                    'filter'=>false
                ),
                array(
                    'name'=>'total',
                    'value'=>'"R ".number_format($data->bandwidth, 2)*$data->price',
                    'filter'=>false
                ),
        array(
            'class'=>'CButtonColumn',
        ),
    ),
));
$this->endWidget();
?>