Conditionally including stylesheets in the layout depending on the controller's name

Question

I am learning the ASP.NET MVC 3 Framework. In my layout page (_Layout.cshtml), I would like to conditionally include some CSS stylesheets depending on the name of the controller. How do I do that?

Answer 1

You could obtain the current controller name using the following property:

ViewContext.RouteData.GetRequiredString("controller")

So based on its value you could include or not the stylesheet:

@if (ViewContext.RouteData.GetRequiredString("controller") == "somecontrollername")
{
    <link href="@Url.Content("~/Content/Site.css")" rel="stylesheet" type="text/css" />
}

Or use a custom helper:

public static class CssExtensions
{
    public static IHtmlString MyCss(this HtmlHelper html)
    {
        var currentController = html.ViewContext.RouteData.GetRequiredString("controller");
        if (currentController != "somecontrollername")
        {
            return MvcHtmlString.Empty;
        }

        var urlHelper = new UrlHelper(html.ViewContext.RequestContext);
        var link = new TagBuilder("link");
        link.Attributes["rel"] = "stylesheet";
        link.Attributes["type"] = "text/css";
        link.Attributes["href"] = urlHelper.Content("~/Content/Site.css");
        return MvcHtmlString.Create(link.ToString(TagRenderMode.SelfClosing));
    }
}

and in layout simply:

@Html.MyCss()

Answer 2

I would use different approach. Define base controller instead and define method SetStyleSheet like:

public abstract class BaseController : Controller
{
    protected override void Intialize(RequestContext requestContext)
    {
        base.Initialize(requestContext);
        SetStyleSheet();
    }

    protected virtual void SetStyleSheet()
    { }
}

In derived classes you can override SetStyleSheet to set something like ViewData["styleSheet"] and use it for example in your master page (_Layout.cshtml).