Well, the wiki page you found is really a good start...
Here is an alternative way for doing this :
In your Profile model :
// private username attribute, will be used on search
private $_username;
public function rules()
{
return array(
// .....
array('username', 'safe', 'on'=>'search'),
// .....
);
}
public function getUsername()
{
// return private attribute on search
if ($this->scenario=='search')
return $this->_username;
// else return username
if (isset($this->user_id)) && is_object($this->user))
return $this->user->username;
}
public function setUsername($value)
{
// set private attribute for search
$this->_username = $value;
}
public function search()
{
// .....
$criteria->with = 'user';
$criteria->compare('user.username', $this->username, true);
// .....
return new CActiveDataProvider($this, array(
'criteria'=>$criteria,
'sort'=>array(
'attributes'=>array(
'username'=>array('asc'=>'user.username', 'desc'=>'user.username DESC'),
'*',
),
),
));
}
And in your view you should simply try :
$this->widget('zii.widgets.grid.CGridView', array(
'id'=>'profile-grid',
'dataProvider'=>$model->search(),
'filter'=>$model,
'columns'=>array(
// .....
'username',
// .....
),
);