I want to create a block dynamically but not render it within the layout hierarchy (I am going to save the output).

Is there any reason to use Layout::createBlock() in this case or can I instantiate it directly with a factory? Or even inject the block itself as shared instance into the class where I'm using it?

I would prefer to avoiding the unnecessary dependency to the layout and the additional abstraction but I am not sure what might break if the block is not associated to the layout.

2 Answers 2


if you don't do it via Layout::createBlock some of the methods you might call from that block will throw exceptions or return an empty string.
Here are some examples (all of them from \Magento\Framework\View\Element\AbstractBlock):

  • getChildNames
  • setChild
  • addChild
  • unsetChild
  • unsetChildren
  • getChildBlock
  • getChildHtml
  • getChildChildHtml
  • getBlockHtml
  • insert
  • append
  • getGroupChildNames

I would advice to use the createBlock if you want to be politically correct, but if you don't need any of the methods above I see no harm in using the block as a shared instance.

  • I found out that the block still has access to the layout because it is passed on construction via context object, but after checking "addChild" and related methods, I understand that they throw exceptions because $this->_nameInLayout is empty. Thanks for the hint! Sep 22, 2016 at 8:47

Layout::createBlock() is useful if the block is a CMS block or page that has {{...}} content such as widgets or variables. If you don't go through the layout, you won't get these elements.

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