Razor directives for preprocessors

Problem

I’m working on my first Razor page today, and I’m having trouble figuring out how to enter it.

#if debug
...
#else
...
#endif

How can I accomplish this in Razor?

Asked by mamu

Solution #1

I’ve just built a new mechanism for adding extensions:

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

Then I utilized it in my arguments as follows:

<section id="sidebar">
     @Html.Partial("_Connect")
     @if (!Html.IsDebug())
     { 
         @Html.Partial("_Ads")
     }
     <hr />
     @RenderSection("Sidebar", required: false)
</section>

It works because the helper is compiled with the DEBUG/RELEASE symbol.

Answered by Shawn Wildermuth

Solution #2

HttpContext already has this:

@if (HttpContext.Current.IsDebuggingEnabled)
{
    // Means that debug="true" in Web.config
}

This, in my opinion, makes more sense for views than conditional compilation and is useful in some testing cases. (For more on this, see Tony Wall’s comment below.)

Alex Angas remarked that this solution causes a NullReferenceException, and a few people have upvoted, showing that this isn’t an unique incident.

HttpContext is my best estimate. Current is saved in CallContext, which means it can only be accessed by the thread handling the incoming HTTP request. You’ll obtain a null value for HttpContext if your views are rendered on a different thread (maybe any alternatives for precompiled views?). Current.

If you receive this error, please let me know in the comments and let me know if you’re using precompiled views or anything else that would cause your views to be rendered/executed partially on another thread!

Answered by Jordan Gray

Solution #3

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

That is, in fact, the correct response. Because all views are compiled in debug mode, you’ll need to pass whether you’re in debug mode via the Model. (or ViewBag).

Answered by Buildstarted

Solution #4

Instead of testing the preprocessor variables in.NET Core, you can use the environment tag helper:

<environment include="Development">
    <!--Debug code here-->
</environment>

Answered by beleester

Solution #5

You can always use the Request.IsLocal attribute as a debug like test because I’m very sure debug configuration is correlative to the fact that you’re actually executing locally. As an example:

@if (Request.IsLocal)
{
    <link rel="stylesheet" type="text/css" href="~/css/compiled/complete.css">
}
else
{
    <link rel="stylesheet" type="text/css" href="~/css/compiled/complete.min.css">
}

Answered by Sbu

Post is based on https://stackoverflow.com/questions/4696175/preprocessor-directives-in-razor