<?php
class PageResource extends DataObject
{
   static $db = array (
      'Name' => 'Text',
      'Beschreibung' => 'Text'
   );

   static $has_one = array (
      'Attachment' => 'File', //@UncleCheese: could this be the problem?
      'Page' => 'Page'
   );

   public function getCMSFields_forPopup()
   {
      return new FieldSet(
         new TextField('Name'),
         new TextareaField('Beschreibung'),
         new FileIFrameField('Attachment')
      );
   }
}
?>

<?php
class Page extends SiteTree {

   public static $db = array(
      'RedirectToChild'       => 'Int',
      'Headline'             => 'Text',
      'Copytext'             => 'HTMLText',
      'BannerLinkExtern'       => 'Text',
      'BannerLinkInternID'    => 'Text',
      'BannerEinblenden'       => 'Boolean',
      'BannerText'          => 'Text',
      'KopfbildAufStartseite' => 'Boolean',
      'SliderCopytext'       => 'Text'
   );

   public static $has_one = array(
      'MoodImage' => 'Page_MoodImage',
      'BannerImage' => 'Page_BannerImage',
      'BannerLinkIntern' => 'SiteTree'
   );
   
   static $has_many = array (
      'PageResources' => 'PageResource'
   );
   
   function getCMSFields() {
   $array = array(
      '1' => 'Hauptnavigationspunkt anzeigen',
      '2' => 'Direkt 1. Navigationspunkt der 2. Ebene anzeigen',
      '3' => 'Direkt 1. Navigationspunkt der 3. Ebene anzeigen'
   );
   
   
      $fields = parent::getCMSFields();
      $fields->addFieldToTab('Root.Content.Main', new DropdownField(
         'RedirectToChild',
         'Content zeigen aus',
         $array));
      // Kopfbild
      $fields->addFieldToTab('Root.Content.Kopfbild', new CheckboxField('KopfbildAufStartseite', 'Bild im Slider auf der Startseite anzeigen?'));
      $fields->addFieldToTab('Root.Content.Kopfbild', new TextareaField('SliderCopytext', 'Text f&uuml;r Slider:'));
      $fields->addFieldToTab("Root.Content.Kopfbild", new ImageField(
         "MoodImage",
         "Bitte w&auml;hlen Sie ein Kopfbild (491*267)",
         null,
         null,
         null,
         "Kopfbilder/"
         )
      );
      // Banner
      $fields->addFieldToTab('Root.Content.Bannerbild', new ImageField(
         'BannerImage',
         'Bitte w&auml;hlen Sie ein Bild (260*120)',
         null,
         null,
         null,
         'Bannerbilder/'
         )
      );
      $fields->addFieldToTab('Root.Content.Banner', new TextField('Headline'));
      $fields->addFieldToTab('Root.Content.Banner', new TextareaField('Copytext'));
      // TreeDropdownField: $name, $title, $sourceObject, $keyField, $labelField, $showSearch
      
      $verlinkung = new TreeDropdownField('BannerLinkInternID', 'Bitte eine interne Verlinkung w&auml;hlen', 'SiteTree', 'ID', 'Title', true);
      // $verlinkung->objectForKey('ID');
      // $verlinkung->objectForKey($BannerLinkInternID);
      $fields->addFieldToTab('Root.Content.Banner', $verlinkung);
      
      $fields->addFieldToTab('Root.Content.Banner', new TextField('BannerLinkExtern'));
      $fields->addFieldToTab('Root.Content.Banner', new CheckboxField('BannerEinblenden'));

      $manager = new FileDataObjectManager(
         $this, // Controller
         'PageResources', // Source name
         'PageResource', // Source class
         'Attachment', // File name on DataObject
         array(
            'Name' => 'Name',
            'Beschreibung' => 'Beschreibung',
         ), // Headings
         'getCMSFields_forPopup' // Detail fields (function name or FieldSet object)
         // Filter clause
         // Sort clause
         // Join clause
      );
$fields->addFieldToTab("Root.Content.Dateien",$manager);
      
      return $fields;
   }

}