Orchard CMS pass data from View to Theme layout

Question

I'm writing a custom Orchard module with a custom Theme. I would like to pass data from the View back to the Layout to change the layout based on data determined in the View.

In my example, I have a left-nav in my theme - certain views should be able to instruct the layout not to render this left-nav.

In standard mvc 3 I would just pass the value up through the ViewBag, but this doesn't seem to be working within Orchard - I'm guessing that the layout code is executed before the View is rendered?

I've looked into using a Shape to move this data around but looks like it might be a little heavyweight for what i'm trying to achieve.

What's the best practice for passing data around like this as an alternative to ViewBag?

Update: After playing around with it a bit more i've just noticed that TempData is being picked up in the Layout - can anyone explain why TempData is transmitted, but ViewData isn't? And is it safe to use from an Orchard POV?

Answer 1

It's easier than that... All templates have access to the Layout shape, which is a dynamic object. This means that you can modify it on the fly, add it properties, etc. In your specific case, suppressing a zone, you may even be able to just set that to null: zones are just shapes, and in the case of top-level zones they are expandos on Layout. So if you have a zone named Foo, setting Layout.Foo to null should do the trick. As a matter of facts, I'm doing exactly that in one of my themes, to suppress the side bars from my error pages without having to create a specific widget layer:

Layout.AsideFirst = null;
Layout.AsideSecond = null;