C# and ASP.NET MVC: Using #if directive in a view

Question

I've got a conditional compilation symbol I'm using called "RELEASE", that I indicated in my project's properties in Visual Studio. I want some particular CSS to be applied to elements when the RELEASE symbol is defined, and I was trying to do that from the view, but it doesn't seem to be working.

My view code looks like this (shortened a bit for demo purposes):

<% #if (RELEASE) %>
    <div class="releaseBanner">Banner text here</div>
<% #else %>
    <div class="debugBanner">Banner text here</div>
<% #endif %>

With this code, and with the RELEASE symbol set, the 'else' code is running and I'm getting a div with the debugBanner class. So it doesn't seem to think that RELEASE is defined. It's worth noting that my actual C# code in .cs files is recognizing RELEASE and runs the correct code. It's only the view that is giving me the problem.

Does anyone have any insight into this? Any help would be appreciated. Thanks.

Clarification: I should have mentioned that this view is already a partial view, and I'll simply render it in pages where I need it. That's because these banners will be on certain pages and not others. So even when rendering it as a partial view via:

Html.RenderPartial("BannerView");

it's not working.

Why don't you create a html helper method and put your code in there? You can then do the if and do a render partial to keep the HTML — Rippo
– Rippo, Commented Jun 1, 2010 at 15:43
Not too familiar with html helper methods. I did clarify my question to indicate that this is a partial view I'm working with. Can you elaborate a bit on your suggestion? — MegaMatt
– MegaMatt, Commented Jun 1, 2010 at 15:47
preprocessor directives only work @ compile-time... @DeveloperArt has an elegant solution... — Alex
– Alex, Commented Jun 1, 2010 at 15:53
Adding the keyword "constant" to this page so it gets returned for searches for "compiler constants". (hopefully) — G-Wiz
– G-Wiz, Commented Apr 8, 2011 at 20:24
See: stackoverflow.com/a/8325519/204699 for another alternative to using conditional compilation in views. — João Angelo
– João Angelo, Commented Nov 30, 2011 at 12:14

UpTheCreek · Accepted Answer · 2013-05-30 17:59:51Z

108

I ~~recently~~ discovered that you can simply test:

HttpContext.Current.IsDebuggingEnabled

in Views, which saves you checking symbols in other parts of your app.

edited May 30, 2013 at 17:59

answered Dec 22, 2010 at 13:56

UpTheCreek

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3 Comments

Ed DeGagne Over a year ago

This is the best approach, IMO.

drzaus Over a year ago

Shouldn't you use this.Context.IsDebuggingEnabled instead? Really only applicable if you've mocked the context or somehow used razor views outside of a webapp

carloswm85 Over a year ago

I've tested this in development environment, and by publishing locally (my machine, to a folder, .pubxml) using IIS , and it works just fine. Year 2022, using VS22, in NET Framework 4.8 project.

Birdman · Accepted Answer · 2012-01-14 21:48:21Z

61

A better, more generic solution is to use an extension method, so all views have access to it:

public static bool IsReleaseBuild(this HtmlHelper helper)
{
#if DEBUG
    return false;
#else
    return true;
#endif
}

You can then use it like follows in any view (razor syntax):

@if(Html.IsReleaseBuild())
...

answered Jan 14, 2012 at 21:48

Birdman

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3 Comments

drzaus Over a year ago

of course, the caveat is that it depends on where this method is -- if it's in a shared library that has been compiled in release mode, it'll return false when included in a project compiled in debug mode.

chemitaxis Over a year ago

Please check this question stackoverflow.com/questions/28400135/…

SJaka Over a year ago

Where this method should be placed? In a controller? A separate class?

user151323 · Accepted Answer · 2010-06-01 15:49:48Z

17

In your model:

bool isRelease = false;

<% #if (RELEASE) %>
    isRelease = true;
<% #endif %>

In your view:

<% if (Model.isRelease) { %>
    <div class="releaseBanner">Banner text here</div>
<% } else { %>
    <div class="debugBanner">Banner text here</div>
<% } %>

answered Jun 1, 2010 at 15:49

user151323

6 Comments

MegaMatt Over a year ago

I'm gathering from this answer that it's not possible to check compilation symbols from a view, and that is must be done from a .cs file. Is this true?

Alex Over a year ago

Nice solution, but what about placing this logic in a base controller that all Controllers inherit. Then you could have access of this property through all Controllers...

MegaMatt Over a year ago

well, not sure that would completely work xander. To have access to it from the view, we would need a Model with that property, not a Controller with that property. So I'd really have to pass that same Model from multiple controllers and render that view, which would be sort of a pain.

Alex Over a year ago

If you place that logic in a base controller and access it from a derived controller then you could assign it to ViewData or some custom ViewModel

MegaMatt Over a year ago

So actually, what I'm going to do is set a property in one of our Global files, which should solve the problem. Same general principle as Develop Art's solution, but slightly tweaked. Thanks for the responses.

|

d.popov · Accepted Answer · 2013-06-11 09:47:41Z

9

@if (HttpContext.Current.IsDebuggingEnabled)
{
    // Debug mode enabled. Your code here. Texts enclosed with <text> tag
}

answered Jun 11, 2013 at 9:47

d.popov

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Comments

Nigrimmist · Accepted Answer · 2015-05-19 16:13:21Z

3

You can use ViewBag instead of viewmodel (but viewmodel-like approach is better) :

Controller :

controller code

View :

@{
   bool hideYoutubeVideos = ViewBag.hideYoutubeVideos ?? false;     
}

Usage :

@if (!hideYoutubeVideos)
{
     <span>hello youtube</span>
}

Also, be sure, that NIKITA_DEBUG variable exist in build tab of your project :

build tab

answered May 19, 2015 at 16:13

Nigrimmist

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Comments

Matheus Fernandes Amorim · Accepted Answer · 2018-01-04 12:37:21Z

1

For me, the code below has worked very well. When the application is Debugging my buttons appear, when is Release, don't.

@if (this.Context.IsDebuggingEnabled)
{
    <button type="button" class="btn btn-warning">Fill file</button>
    <button type="button" class="btn btn-info">Export file</button>
}

answered Jan 4, 2018 at 12:37

Matheus Fernandes Amorim

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Comments

Leniel Maccaferri · Accepted Answer · 2021-03-16 21:42:58Z

0

You can use Debugger.IsAttached like this:

@using System.Diagnostics

@{
    string gridID = $"the-grid-7";

    if (Debugger.IsAttached)
        gridID = gridID + new Random().Next(1, 1000).ToString();

    var loadUrl = ViewBag.LoadUrl;
}

answered Mar 16, 2021 at 21:42

Leniel Maccaferri

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Comments

Artur · Accepted Answer · 2020-01-21 15:26:06Z

-5

Below is the Razor syntax for conditional compiler directives. It loads the developer version of jquery when DEBUG variable is set in VS profile or web.config. Otherwise the min version is loaded.

    @{
#if (DEBUG)
    }
        <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.6/jquery.js"></script>
        <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jqueryui/1.8.12/jquery-ui.js"></script>
    @{    
#else
    }
        <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.6/jquery.min.js"></script>
       <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jqueryui/1.8.12/jquery-ui.min.js"></script>
    @{
#endif
    }

edited Jan 21, 2020 at 15:26

Artur

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answered Jul 12, 2011 at 17:06

Aubrey Cote

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4 Comments

Tom Over a year ago

don't think this will work since the views aren't compiled and if(DEBUG) is a compiler directive?

trailmax Over a year ago

That does not work in Razor. That is exactly what the original question about.

Artur Over a year ago

I edited the post to match the current razor sytnax, which this answer was for. This is not "classic ASP" syntax, but it is the "ASP.NET Web Pages (Razor) 3", which is the current one I believe.

Artur Over a year ago

You will need to recompile the views and it does not seem to consistently work either, so better go with the Helper approach.

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