controller_action_predispatch_checkout_onepage_index应该是您要查找的事件.所有控制器都继承preDispatch方法，该方法将触发预调度的一般事件，并根据请求的操作路径触发特定事件.所需的控制器位于checkout模块中，称为onepage，默认操作为index.

controller_action_predispatch_checkout_onepage_index should be the event you're looking for. All controllers inherit the preDispatch method which fires a generic event for predispatch, and a specific event based on the requested action path. The controller you want lives in the checkout module and is called onepage with a default action of index.

查看Mage_Core_Controller_Varien_Action::preDispatch()以查看相关代码