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

问题

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.

回答1:

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>
<% } %>

回答2:

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

HttpContext.Current.IsDebuggingEnabled

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

回答3:

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())
...

回答4:

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

回答5:

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

Controller :

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 :

回答6:

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>
}

回答7:

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
}

来源：https://stackoverflow.com/questions/2951128/c-sharp-and-asp-net-mvc-using-if-directive-in-a-view

标签

asp.net-mvc

conditional

debug-symbols