Magento-控制器到Ajax估计发货：加载块并显示phtml

我复制了estimatePostAction并制作了estimateAjaxPostAction（覆盖核心-我没有破解核心）。控制器操作也起作用（类Mage\u Checkout\u CartController）

现在，我想获得/创建一个块，用于在使用ajax估计发货后替换发货块。我试过这个：

public function estimateAjaxPostAction()
{
    $country    = (string) $this->getRequest()->getParam('country_id');
    $postcode   = (string) $this->getRequest()->getParam('estimate_postcode');
    $city       = (string) $this->getRequest()->getParam('estimate_city');
    $regionId   = (string) $this->getRequest()->getParam('region_id');
    $region     = (string) $this->getRequest()->getParam('region');

    $this->_getQuote()->getShippingAddress()
    ->setCountryId($country)
    ->setCity($city)
    ->setPostcode($postcode)
    ->setRegionId($regionId)
    ->setRegion($region)
    ->setCollectShippingRates(true);
    $this->_getQuote()->save();
    //$this->_goBack();

    $this->loadLayout();
    $block = $this->getLayout()->createBlock('Mage_Checkout_Block_Cart_Shipping','checkout.cart.shipping.ajax',array('template' => 'checkout/cart/shipping.phtml'));
    if($block) {
        $response = array();
        $response['shipping'] = $block->toHtml();
        $this->getResponse()->setBody(Mage::helper('core')->jsonEncode($response));
    }
}

创建了block checkout.cart.shipping.ajax。但是toHtml（）不返回任何内容。 我的JSON返回：

{“运送”：“”}

为什么

toHtml

方法不起作用

编辑：我的区块码（checkout/cart/shipping.phtml）

丹尼斯。。。我有修改代码，请检查

    public function estimateAjaxPostAction()
{
    $country    = (string) $this->getRequest()->getParam('country_id');
    $postcode   = (string) $this->getRequest()->getParam('estimate_postcode');
    $city       = (string) $this->getRequest()->getParam('estimate_city');
    $regionId   = (string) $this->getRequest()->getParam('region_id');
    $region     = (string) $this->getRequest()->getParam('region');

    $this->_getQuote()->getShippingAddress()
    ->setCountryId($country)
    ->setCity($city)
    ->setPostcode($postcode)
    ->setRegionId($regionId)
    ->setRegion($region)
    ->setCollectShippingRates(true);
    $this->_getQuote()->save();
         $response = array();
        $response['shipping']=$this->eastmatesajax();
        $this->getResponse()->setBody(Mage::helper('core')->jsonEncode($response));
        }
       protected function eastmatesajax()
    {

        $layout=$this->getLayout();
        $layout->getMessagesBlock()->setMessages(Mage::getSingleton('checkout/session')->getMessages(true),Mage::getSingleton('catalog/session')->getMessages(true)); 
        $block = $this->getLayout()->createBlock('checkout/cart_shipping')->setTemplate( 'checkout/cart/shipping.phtml');
        return $block->toHtml();
    }

使用
$this->_getQuote（）->collectTotals（）解决更新的区块问题
在
$this->_getQuote（）->save（）之前
它可以工作。谢谢您能解释一下为什么我需要创建另一个函数吗？第一次渲染显示估计通知此解决方案用于调用块，但块未更新。在多次使用不同邮政编码的请求之后，结果总是相同的。只有在新页面加载后，最后一次查询的结果才会正确显示。就像控制器中的会话没有更新一样。@AmitBera，对我来说，
$block
返回null。
    public function estimateAjaxPostAction()
{
    $country    = (string) $this->getRequest()->getParam('country_id');
    $postcode   = (string) $this->getRequest()->getParam('estimate_postcode');
    $city       = (string) $this->getRequest()->getParam('estimate_city');
    $regionId   = (string) $this->getRequest()->getParam('region_id');
    $region     = (string) $this->getRequest()->getParam('region');

    $this->_getQuote()->getShippingAddress()
    ->setCountryId($country)
    ->setCity($city)
    ->setPostcode($postcode)
    ->setRegionId($regionId)
    ->setRegion($region)
    ->setCollectShippingRates(true);
    $this->_getQuote()->save();
         $response = array();
        $response['shipping']=$this->eastmatesajax();
        $this->getResponse()->setBody(Mage::helper('core')->jsonEncode($response));
        }
       protected function eastmatesajax()
    {

        $layout=$this->getLayout();
        $layout->getMessagesBlock()->setMessages(Mage::getSingleton('checkout/session')->getMessages(true),Mage::getSingleton('catalog/session')->getMessages(true)); 
        $block = $this->getLayout()->createBlock('checkout/cart_shipping')->setTemplate( 'checkout/cart/shipping.phtml');
        return $block->toHtml();
    }