private function AddCategoryField()       
    {
        $name = 'Category';
        $value = '';
        if ($this->article->Exists()) {
            $value = $this->article->GetCategory()->GetID();
        }
        $field = new Select($name, $value);
        $field->AddOption('', Trans('Core.PleaseSelect'));
        $catList = new CategoryListProvider($this->archive);
        $categories = $catList->ToArray();
        foreach ($categories as $category) {
            $field->AddOption($category->GetID(), $category->GetName());
        }
        $this->AddField($field);
        $this->SetRequired($name);
    }