Magento - 在页面左边显示三层分类

步骤 I.编辑layout/catalog.xml

在<default>标签下，加入如下代码

<reference name="left">
  <block type="catalog/navigation" name="catalog.vertnav" template="catalog/navigation/vert_nav.phtml" />
</reference> 

步骤II. 在 template/catalog/navigation/目录下创建一个名为vert_nav.phtml 的文件,代码如下:

    <div class="vertical-nav-container box base-mini">
      <div id="vertical-nav">
       <div class="head">
         <h4><?php echo $this->__('Categories') ?></h4>
       </div>
       <ul id="nav_vert">
         <?php foreach ($this->getStoreCategories() as $_categoryNode): ?>
         <?php $open = $this->isCategoryActive($_categoryNode); ?>
         <?php $hasChildren = $_categoryNode->hasChildren(); ?>
          <li>
            <a href="<?php echo $this->getCategoryUrl($_categoryNode); ?>"<?php if($open) { echo ' class="open"'; } ?><?php if($hasChildren) { echo ' class="potential"'; } ?> >
             <?php if($hasChildren&&$open) { echo '- '; } elseif($hasChildren) { echo '+ '; }else{ echo ' '; }?><?php echo $_categoryNode->getName();?>
            </a>
            <?php if ($open && $hasChildren): ?>
            <ul>
             <?php foreach ($_categoryNode->getChildren() as $sonCategoryNode): ?>
             <?php $subCat = Mage::getModel('catalog/category')->load($sonCategoryNode); ?>
             <?php $open = $this->isCategoryActive($subCat); ?>
             <?php $hasChildren = $subCat->hasChildren(); ?>
             <li>
               <a href="<?php echo $this->getCategoryUrl($subCat); ?>"<?php if($open) { echo ' class="subopen"'; } ?><?php if($hasChildren) { echo ' class="potential"'; } ?><?php if(!$hasChildren&&$open) { echo ' class="final"'; } ?> >
                <?php if($hasChildren&&$open) { echo '- '; } elseif($hasChildren) { echo '+ '; }?><?php echo $subCat->getName(); ?>
               </a>
               <?php if ($open && $hasChildren): ?>
                <ul>
                  <?php foreach ($sonCategoryNode->getChildren() as $grandsonCategoryNode): ?>
                   <?php $subsubCat = Mage::getModel('catalog/category')->load($grandsonCategoryNode); ?>
                   <?php $open = $this->isCategoryActive($subsubCat) ?>
                   <?php $hasChildren = $grandsonCategoryNode->hasChildren(); ?>
                   <li>
                     <a href="<?php echo $this->getCategoryUrl($subsubCat); ?>" <?php if($open) { echo ' class="final"'; } ?>>
                      <?php if($hasChildren) { echo '+ '; }?><?php echo $subsubCat->getName(); ?>
                     </a>
                   </li>
                  <?php endforeach; ?>
                </ul>
               <?php endif; ?>
             </li>
             <?php endforeach; ?>
            </ul>
            <?php endif; ?>
          </li>
         <?php endforeach ?>
       </ul>
      </div>
    </div>

注意上面的代码$this->getStoreCategories()得到的不是Mage_Catalog_Model_Category类的实例，而是Varien_Data_Tree_Node类的实例

步骤III. 在添加到 skin/[yourinterface]/[yourtheme]/css/menu.css 文件里增加下面的代码

#vertical-nav ul {
  list-style-type: none; /* get rid of the bullets */
  padding:0; /* no padding */
  margin:0; /* no margin for IE either */
}

#vertical-nav ul li {
  margin: 0;
  padding: 0;
  display:block;
  margin-top: 1px; /* lines */
}

#vertical-nav ul ul li a,#vertical-nav ul li{
  background-color: #FFFFFF;
}

#vertical-nav ul li a {
  display: block;
  padding: 3px 3px 3px 23px;
  margin:0;
  text-decoration: none;
  height:15px; /* hint for IE, alternatively remove whitespace from HTML */
  background-color: #CCCCCC;
}

#vertical-nav ul li .open, #vertical-nav .activesubsub, #vertical-nav .subopen {
  font-weight: bolder;
  text-decoration: underline;
  color:#000000
}

#vertical-nav .final{
  background-color:#ECECEC;
}

#vertical-nav ul ul li a {
  margin-left: 20px;
}

#vertical-nav ul ul ul li a {
  margin-left: 40px; /* indent level 2 */
}

#vertical-nav a {
  color:#999999;
}

#vertical-nav a:hover {
  color:#666666;
}
#vertical-nav ul li ul li a {
  border-top-width: thin;
  border-bottom-width: thin;
  border-top-style: dotted;
  border-bottom-style: dotted;
  border-top-color: #CCCCCC;
  border-bottom-color: #CCCCCC;
  margin-bottom:0px;
  margin-top:0px;
}

#vertical-nav ul li ul li {
  margin-bottom:0px;
  margin-top:0px;
}

进入一个layout有左列显示的网页（如任一产品分类页），你将可能看到如下的代码：

注：如果点击"两岁到三岁"分类，将进入该分类页面，但是该分类显示将不被展开。因为本例只是最多显示三层分类结构