class ArticlePage extends Page {
   static $icon = "themes/tutorial/images/treeicons/news";
   static $defaults = array(
   'ProvideComments' => true
   );

   static $db = array(
      'Date' => 'Date',
      'Author' => 'Text'
   );
   static $has_one = array(
   );
   function getCMSFields() {
      $fields = parent::getCMSFields();
      $fields->addFieldToTab('Root.Content.Main', $dateField = new DateField('Date','Article Date (for example: 20/12/2010)'), 'Content');
      $dateField->setConfig('showcalendar', true);
      $dateField->setConfig('dateformat', 'dd/MM/YYYY');
      $fields->addFieldToTab('Root.Content.Main', new TextField('Author','Author Name'), 'Content');
      return $fields;
   }
}

class ArticlePage_Controller extends Page_Controller {

   public function ApplyForm() {
      $form = new Form (
         $this,
         "ApplyForm",
         new FieldSet (
            new TextField('ViewTitle', 'Title'),
            new TextareaField('ViewDescription', 'Description'),
            new HiddenField('ArticleTitle', _t('FileAttach.ARTICLETITLE'), $this->Title ),
            new HiddenField('ArticleID', _t('FileAttach.ARTICLEID'), $this->ID ),
            $file = new FileUploadField('Attachment', _t('FileAttach.ATTACHMENT','Upload a File'))
         ),
         new FieldSet (
         new FormAction('doApply', _t('FileAttach.ATTACHMENT','Add File'))
         ),
         new RequiredFields('ViewTitle')
      );
      $file->setFileTypes(array(
         'pdf',
         'jpg'
      ));
      return $form;
   }

   public function doApply($data, $form) {
      $form->saveInto($application = new FileAttach());
      $application->write();
      return array (
      'Application' => $application
   );
   }

   function GetFiles() {
      $id = $this->ID;
      $obj         = "FileAttach";
      $filter       = "ArticleID = $id";
      $sort         = "";
      $join         = "LEFT JOIN File ON (File.ID = FileAttach.AttachmentID)";
      $limit         = "";
      $data = DataObject::get($obj, $filter, $sort, $join, $limit);
      return $data;
   }

}

<% include Menu2 %>
<div id="Content" class="typography">
<% include Breadcrumbs %>

<h1>$Title</h1>
   $Content

<div class="newsDetails">
PAGE ID $ID Posted on $Date.Nice by $Author
$ApplyForm
<div>
<% control GetFiles %>
      <div>$ID $ViewTitle $ViewDescription</div>
      $Attachment.CMSThumbnail
<% end_control %>
</div>
</div>
</div>

class FileAttach extends DataObject {

   static $db = array (
      'ViewTitle' => 'Text',
      'ViewDescription' => 'Text',
      'ArticleTitle' => 'Text',
      'ArticleID' => 'Varchar',
   );

   static $has_one = array (
      'Attachment' => 'File'
   );

   public function getCMSFields_forPopup() {
    return new FieldSet(
    new TextField('ViewTitle', 'Title'),
    new TextareaField('ViewDescription', 'Description'),
    new ImageField('File', 'File')

    );
   }

   public function getCMSFields() {
      $f = parent::getCMSFields();
      $manager = new ImageDataObjectManager(
      $this, // Controller
      'Attachment', // Source name
      'File', // Source class
      'ApplyForm', // File name on DataObject
      array(
      'Title' => 'Title',
      'Caption' => 'Caption'
      ), // Headings
      'getCMSFields_forPopup' // Detail fields
      // Filter clause
      // Sort clause
      // Join clause
      );
      $f->addFieldToTab("Root.Content.Gallery",$manager);
      return $f;
   }
}