CODEWITHSUNDEEP
asp.netasp.net-mvcroutesasp.net-mvc-routing
steinberg
steinberg

Reputation: 620

How to make IRouteConstraint filter route

I wrote a custom route constraint, but its filter just doesn't get recognized. Does anyone have an example working use of IRouteConstraint ?

Also, note to developers: I get double display of the form on my android. Something must be wrong with the partial rendering?

Upvotes: 18

Views: 9405

Answers (1)

dahlbyk
dahlbyk

Reputation: 77540

Here's a simple constraint that looks up an article slug in a fictional repository:

public class SlugRouteConstraint : IRouteConstraint
{
    private readonly ISlugRepository slugRepository = new SlugRepository();

    public bool Match(HttpContextBase httpContext, Route route, string parameterName, RouteValueDictionary values, RouteDirection routeDirection)
    {
        if (!values.TryGetValue(parameterName, out object slug))
            return false;

        return slugRepository.Exists(slug as string);
    }
}

You could wire up the constraint like this:

routes.MapRoute("Slugs", "{slug}",
    new { controller = "Articles", action = "View" },
    new { slug = new SlugConstraint() });

Upvotes: 23

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