Nette\Forms\Controls\UploadControl::loadHttpData PHP Method

    public function loadHttpData()
    {
        $this->value = $this->getHttpData(Nette\Forms\Form::DATA_FILE);
        if ($this->value === NULL) {
            $this->value = new FileUpload(NULL);
        }
    }

 public function loadHttpData()
 {
     parent::loadHttpData();
     if (!$this->uploadPath) {
         throw new \Exception('Path for uploading must be set.');
     }
     $this->validate();
     $this->isValidated = TRUE;
     // Disable validation
     if ($this->checkbox->isOk()) {
         // Checkbox process
         $this->checkbox->loadHttpData();
         $this->delete = $this->checkbox->getValue();
         if ($this->delete && !$this->isRequired()) {
             $this->value = NULL;
         } else {
             if (!$this->isRequired()) {
                 $this->value = $this->defaultValue;
             }
         }
     } else {
         if (!$this->value->isOk()) {
             $this->value = NULL;
         }
     }
     if ($this->isRequired() && $this->checkbox->isOk() && !$this->checkbox->getValue()) {
         $this->addError($this->getFilledMessage());
         return;
     }
 }