Rendering a z3cform Wizard as a standalone view

Question

Plone/Zope's z3cforms inherit from BrowserPage, and therefore should be able to be rendered without the use of an additional View and View Class. When I try to do this, the form renders fine, but none of the form's fields appear. I am trying to solve why this occurs. Keep in mind this example is using collective.z3cform.wizard, which essentially provides two classes, a Wizard and a Step. A Wizard is a Form (capital F) that mostly provides the machinery to glue the Steps together and maintain state with sessions, and a Step is just a Form.

To me, it feels like either the macro is incorrect, the context is wrong, or there needs to be some wrapping/unwrapping of the form. Basically, I feel like there's some one magic line of code or piece of information I'm missing, which is often the case with Plone.

When the form is wired up to use a separate view (which is redundant), the form renders fine with all the fields showing.

Since I understand this is complex, I've built an example-only standalone package on GitHub that showcases the problem. If you install this package into a stock Plone site with buildout, you will get three views:

http://localhost:8080/Plone/working
http://localhost:8080/Plone/almost
http://localhost:8080/Plone/broken

The working view requires a separate view and a whole-template-wrapping TAL tag, which is both kludge and redundant...but it works and renders the form with all of its fields.

The broken view is wired up how it should be, with the form instance representing the view itself, with the template defined in the Wizard class.

The almost view is identical to the broken view, except that the template is associated with the Wizard's Step rather than the Wizard itself. This results in a broken render, but the form renders with all of its fields.

I hope someone can help me trace down why exactly it is that the broken view renders the form, complete with buttons, but none of the form's fields.

Thank you in advance.

Answer 1

Your broken view does not render the fields because it does not try to render the current step. The default wizard template has something like this in it:

<div tal:define="form nocall:view/currentStep"
   tal:replace="structure form/render" />

which looks up the current step and renders it. But you've overridden that with your own template which just calls the ploneform-macros, which is a generic z3c.form thing that knows nothing about the existence of steps.

You should stick with the default wizard template instead of overriding it, or if you need to customize it you should copy the default wizard.pt from collective.z3cform.wizard as a starting point.

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Meanwhile, your 'almost' view is indeed almost working. The problem here is that the wizard's default template renders the step's template in the middle...but your step's template is set up to produce a full html page (because it uses the master macro from main_template). If you need to customize this template, I would again recommend starting by copying the default step template from c.z.wizard (wizard-step.pt)