块 Mage_Catalog_Block_Product_List 继承 Varien_Object 包含方法 getData（）和 setData（）的类以及魔术方法 get *（）和 set *（）。这些方法允许我们在对象中存储（你猜到）键控数据。

< action /> 标签在XML中允许我们对块实例执行方法调用。您的第二个示例就近了，但语法是：

 < block type =catalog / product_list =bestsellers> 
< action method =setLimit>< value> 3< / value>< / action& 
< / block> 
 

这相当于：

 < block type =catalog / product_listname =bestsellers> 
< action method =setData>< key> limit< / key>< value> 3< / value>< / action& 
< / block> 
 

这大致相当于：

  $ block = new Mage_Catalog_Block_Product_List（）; 
 $ block-> setLimit（3）; 
 

在对象中设置数据，我们现在可以通过 getData ）$ this-> getLimit（）通过调用或或 $ this-> getData（'limit'）制作我们的块代码：

   - > setPageSize（$ this-> getLimit（））
  - > setCurPage（1）; 
 

您应该检查 limit 数据，如果XML中没有提供，则提供默认值。

注意： < action /> 标记无关紧要。这是重要的参数的顺序。我们可以直接调用< action method =setLimit>< foo> 3< / foo>< / action> 。

I've got a bestsellers module which I've written and it works great, however I want to be able to change the collection size it returns via the XML, rather than the php/phtml.

Something like this:

    <block type="catalog/product_list" name="bestsellers" limit="3" 
template="custom/bestsellers.phtml" />

or something like:

    <block type="catalog/product_list" name="bestsellers" 
template="custom/bestsellers.phtml">
         <action method="setLimit">3</action>
    </block>

Is this possible?

I'm currently changing the limit via the phtml with:

->setPageSize(3)
->setCurPage(1);

But that is hard coded and nasty, I need to be able to use my phtml file as template for many cases of the bestsellers module being called from anywhere with the XML + limit in the XML.

Thanks in advance if anyone can shed light on this!

The block Mage_Catalog_Block_Product_List inherits from the Varien_Object class which contains the methods getData() and setData(), as well as the magic methods get*() and set*(). These methods allow us to store (you guessed it) keyed-data within an object.

The <action /> tags in the XML allows us to perform method calls on the block instances. You're nearly there with your second example, but the syntax is:

<block type="catalog/product_list" name="bestsellers">
    <action method="setLimit"><value>3</value></action>
</block>

Which is equivalent to:

<block type="catalog/product_list" name="bestsellers">
    <action method="setData"><key>limit</key><value>3</value></action>
</block>

Which is roughly equivalent to:

$block = new Mage_Catalog_Block_Product_List();
$block->setLimit(3);

With the data set in the object we can now access through the getData() or get*() methods by calling $this->getLimit() or $this->getData('limit') making our block code:

->setPageSize($this->getLimit())
->setCurPage(1);

You should probably perform a check for the existence of the limit data first and provide a default value if none is provided in the XML.

Note: The name of the children in the <action /> tag don't matter. It's the order of the arguments that's important. We could just as well have called <action method="setLimit"><foo>3</foo></action> and it still would have worked.