SeoEngine for filter the link?

You absolutely CAN create a small “SEO indexability engine”. And for your use case (?page=2 indexable, ?sort=hhh not indexable), this is actually the best long-term solution.

Below is a clean, production-ready SEO engine for ASP.NET MVC 5.

What this SEO Engine Will Do

• Decide indexable vs non-indexable
• Handle pagination, sort, filter, search params
• Generate canonical URL
• Control meta robots automatically
• Centralized (no duplicate logic in views)

SEO RULE ENGINE (Concept)

SEO Decision Model

public class SeoResult
{
    public bool IsIndexable { get; set; }
    public string CanonicalUrl { get; set; }
}

SEO Engine (Core Logic)

public static class SeoEngine
{
    private static readonly HashSet<string> NonIndexableParams =
        new HashSet<string>(StringComparer.OrdinalIgnoreCase)
        {
            "sort",
            "filter",
            "search",
            "utm_source",
            "utm_medium"
        };

    public static SeoResult Evaluate(HttpRequestBase request)
    {
        var query = request.QueryString;
        bool hasNonIndexableParam = false;
        
        foreach (string key in query.Keys)
        {
            if (key == null) continue;

            if (NonIndexableParams.Contains(key))
                hasNonIndexableParam = true;
        }

        var baseUrl = request.Url.GetLeftPart(UriPartial.Path);
 
        return new SeoResult
        {
            IsIndexable = !hasNonIndexableParam,
            CanonicalUrl = baseUrl 
        };
    }
}

• Works in ASP.NET MVC 5
• Clean extension syntax
• No breaking changes

Extension Method for HtmlHelper

public static class SeoEngineExtensions
{
    public static SeoResult Evaluate(this HtmlHelper htmlHelper)
    {
        var request = htmlHelper.ViewContext.HttpContext.Request;
        return SeoEngine.Evaluate(request);
    }
}

Use Engine in Controller

public ActionResult Index(int page = 1, string sort = null)
{
    var seo = SeoEngine.Evaluate(Request);

    ViewBag.CanonicalUrl = seo.CanonicalUrl;
    ViewBag.NoIndex = !seo.IsIndexable;

    ViewBag.Page = page;

    return View();
}

Layout (_Layout.cshtml)

<link rel="canonical" href="@ViewBag.CanonicalUrl" />

@if (ViewBag.NoIndex == true)
{
    <meta name="robots" content="noindex, follow" />
}
else
{
    <meta name="robots" content="index, follow" />
}

What This Engine Achieves

• Google-safe
• No duplicate content
• Crawl budget preserved

Why This Is the RIGHT Approach

• Centralized SEO logic
• Easy to extend
• No fragile Razor conditions
• Works with pagination, filters, tracking params
• Matches Google best practices

Also Read

1. How to implement WebSocket in .net for chats?
2. Now Essential Why E-E-A-T Optimization Is for Top Google Rankings
3. How to Implement ChatGPT in a Website (Complete Guide)