Magento Custom module - how to add custom select box with parent categories

I wrote a module to have my own menu bar, rather than just using categories as a menu bar.

So, here I want to show already added menus while adding new menu in the Tab/Form.php in my custom menu module. How can I show all of the existing menu names as a dropdown/options list on the form. Here is the code that I used to have menu form.

 $form = new Varien_Data_Form();
      $this->setForm($form);
      $fieldset = $form->addFieldset('menu_form', array('legend'=>Mage::helper('menu')->__('Menu information')));

  $note = "Name of this Menu";
  $fieldset->addField('title', 'text', array(
      'label'     => Mage::helper('menu')->__('Menu Name'),
      'class'     => 'required-entry',
      'required'  => true,
      'note'      => $note,
      'name'      => 'title',
  ));


  $note = "Menu level";
  $fieldset->addField('level', 'select', array(
      'label'     => Mage::helper('menu')->__('Menu level'),
      'name'      => 'level',
      'note'      => $note,
      'values'    => array(
          array(
              'value'     => 1,
              'label'     => Mage::helpe开发者_如何学Cr('menu')->__('Level 1'),
          ),

          array(
              'value'     => 2,
              'label'     => Mage::helper('menu')->__('Level 2'),
          ),
      ),
  ));

  $model = Mage::registry('menu');
  $fieldset->addField('parent', 'text', array(
        'name' => 'conditions',
        'label' => Mage::helper('menu')->__('Parent Menu'),
        'title' => Mage::helper('menu')->__('Parent Menu'),
        'required' => false,
        'note'      => $note,
  ))->setRule($model)->setRenderer(Mage::getBlockSingleton('rule/conditions'));

 $fieldset->addField('target', 'select', array(
        'label'     => Mage::helper('menu')->__('Open in new window'),
        'name'      => 'target',
        'values'    => array(
            array(
                'value'     => "_blank",
                'label'     => Mage::helper('menu')->__('Yes'),
            ),

            array(
                'value'     => "_self",
                'label'     => Mage::helper('menu')->__('No'),
            ),
        ),
    ));

    $fieldset->addField('status', 'select', array(
        'label'     => Mage::helper('menu')->__('Status'),
        'name'      => 'status',
        'values'    => array(
          array(
              'value'     => 1,
              'label'     => Mage::helper('menu')->__('Enabled'),
          ),

          array(
              'value'     => 2,
              'label'     => Mage::helper('menu')->__('Disabled'),
          ),
        ),
    ));


  $note = "Menu Links to Which page. BaseURL(<b>".str_ireplace("index.php/","",Mage::getBaseUrl())."</b>) Will be Added Dynamically, Please add Your new page Refrence alone";
  $fieldset->addField('menulink', 'text', array(
      'label'     => Mage::helper('menu')->__('URL'),
      'required'  => true,
      'class'     => 'required-entry',
      'note'      => $note,
      'name'      => 'menulink',
  ));


  $fieldset->addField('position', 'select', array(
        'label'     => Mage::helper('menu')->__('Position'),
        'name'      => 'position',
        'values'    => array(
          array(
              'value'     => 1,
              'label'     => Mage::helper('menu')->__('Top 1'),
          ),

          array(
              'value'     => 2,
              'label'     => Mage::helper('menu')->__('Top 2'),
          ),
        ),
  ));



  if ( Mage::getSingleton('adminhtml/session')->getMenuData() )
  {
      $form->setValues(Mage::getSingleton('adminhtml/session')->getMenuData());
      Mage::getSingleton('adminhtml/session')->setMenuData(null);
  } elseif ( Mage::registry('menu_data') ) {
      $form->setValues(Mage::registry('menu_data')->getData());
  }
  return parent::_prepareForm();

In this I want to show all the added menus under the parent menu option. What should I write in my Model class so that I can have a drop down list to show them all, and after adding it should be added to database.

Please help me, am struggling here.

You can do this by adding these lines.

It will show already added menus as a dropdown list so that you can choose any of them as a parent menu for current item.

      $_menus = Mage::getSingleton('menus/menus')->getCollection(); 
      foreach($_menus as $item)
  { 
        if($item->getParent == NULL){
            $_menuItems[] = array(
                        'value'     => $item->getId(),
                        'label'     => $item->getTitle(),
                    );
        }
  }

  $note = "Choose the parent menus for this item";
  $fieldset->addField('parent', 'select', array(
        'name'      => 'parent',
        'label'     => Mage::helper('menus')->__('Parent Menu'),
        'title'     => Mage::helper('menus')->__('Parent Menu'),
        'required'  => false,
        'note'      => $note,
        'class'     => 'HideIt',
        'values'    => $_menuItems,
  ));