Skipping rendering a section in ASP.NET MVC / Razor layouts

Today I had an interesting situation with ASP.NET MVC Razor views. I was dynamically switching layouts based on the host header, and for one layout in particular I wanted to use the layout file to exercise more control of the site than is probably usual.

The reason for this was that this one particular layout was aimed at mobile devices, and so I wanted to skip rendering a couple of the optional sections that the site had to save on a bit of bandwidth.

The views contained standard @section footer { STUFF BE HERE! } type code to render the sections, and the other layouts used @RenderSection("footer", required: false) as placeholders. The normal approach here would probably be to have multiple copies of every view and simply not include the @section declaration in the set of view files aimed at mobile devices, however for various reasons in this project it makes more sense to simply switch the layout (there are a lot of different layouts, so having many versions of a single layout file is much more maintainable than having many different versions of every single view).

When your layout isn’t calling @RenderSection for an area that’s mentioned in a view then you’ll receive the error message “The following sections have been defined but have not been rendered for the layout page“ – which all makes sense and is what you’d expect to happen – but I needed a way around it.

In order to avoid this error and avoid having my sections rendered I ended up using a variation on This fix / hack:

@if(true)
{
          WriteTo(new StringWriter(), RenderSection("footer", false));
}

It might not look overly elegant, but it gets the job done. As long as the view sees the layout trying to do something with each section then it’s happy, even if that something equates to throwing it out the window. Is there a more elegant solution here? Possibly, but in this case the code above is quick and works well.

The original post sets a value on the model to check in the view’s @if statement, which increases the readability of what’s going on – if I was using this in more places than in a single layout I’d probably look to do something similar, but in my case things document themselves a bit in that the layout is quite obviously different from the rest and is a bit of an edge case in itself.

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Posted on Tuesday, November 15, 2011 12:20 PM |

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  • # re: Skipping rendering a section in ASP.NET MVC / Razor layouts
    Gravatar
    Commented on 3/4/2013 10:18 AM

    As an alternative to a StringWriter, I've read using TextWriter.Null can alleviate memory consumption issues (if one were to ever exist) as it's truly throwing it out the window. Obviously such situations would be few and far between; if a section's content were so large that it would cause memory issues, I would assume that an issue itself, but anyway...

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