[TYPO3-mvc] Fluid: form.select view helper and empty default item

[Mam Violeng]

Jochen Rau wrote:

> 
> $this->view->assign('categories', array_merge(array(0 => 'All 
> Categories'), $this->categoryRepository->findAll()));
> 
> in my action method.

Hi,

I used the code like this

$this->view->assign('projectType', array_merge(array(0 => '-- select one 
-- Categories'), $this->projectTypeRepository->findAll()));

in my controller (in new action and edit action), but the problem when I 
don't select any value (default is the first one with value 0) then when 
I submit the form to update or save the value it appear the error bellow.

----
Argument 1 passed to Tx_Extension_Domain_Model_Project::setProjectType() 
must be an instance of Tx_Extension_Domian_Model_ProjectType null given.
----

Any solution to solve this problem?

Thanks,
Violeng