When building web applications in ASP.NET MVC, the layout page (_Layout.cshtml) acts as the common structure shared by all views. It’s where you typically include shared resources like CSS files, JavaScript files, and common HTML elements.

But what if you need a certain CSS file to load on most pages — except for one specific view?

Let’s say you have a CSS file like this:

<link href="~/assets/css/tutorialMenuCss.css" rel="stylesheet" />

You want it included on every page except the "Index" page inside the Home.

Here’s how you can achieve that:

 Solution: Use Razor with RouteData in _Layout.cshtml

razor
@{
    var controller = ViewContext.RouteData.Values["controller"]?.ToString();
    var action = ViewContext.RouteData.Values["action"]?.ToString();
}

@if (!(controller == "Home" && action == "Index")) 
{
    <link href="~/assets/css/tutorialMenuCss.css" rel="stylesheet" />
}

 Why Use This Pattern?

1. Precise Control

You gain fine-grained control over layout content based on the page being rendered. This is useful when some CSS (or JavaScript) files are only relevant to certain pages.

2. Avoid Style Conflicts

Let’s say tutorialMenuCss.css applies styles specific to a tutorial sidebar or menu. If you include this CSS on unrelated pages (like a blog article), it might:

• Apply unnecessary styles

• Clash with other CSS

• Add layout bugs or visual noise

By excluding the file conditionally, you ensure your styles remain modular and clean.

3. Improve Performance

Each unnecessary CSS file adds to the page load time. If you know a CSS file is not needed for a page, don’t load it. That means:

• Fewer HTTP requests

• Smaller render-blocking resources

• Faster page rendering

How It Works

• ViewContext.RouteData.Values["controller"] retrieves the current controller name.

• ViewContext.RouteData.Values["action"] retrieves the current action name.

• You use an if condition to exclude the CSS when you're on the exact page (HomeController → Index).

This check runs server-side during view rendering, so there’s no client-side delay or flicker.

When Should You Use This?

Use this approach when:

• A CSS or script file is only applicable to some pages

• You want to avoid loading heavy or specific assets globally

• You need to avoid CSS or JS conflicts on particular views