CODEWITHSUNDEEP
c#asp.net-mvc-5routes
user806982
user806982

Reputation: 135

Why am I getting 'The parameters dictionary contains a null entry for parameter' for my custom MapRoute

I have a custom route registered in my application, but only the default route is working correctly.

Here are my route mappings:

        routes.MapRoute(
            name: "MyCustomRoute",
            url: "Foo/Index/{myid}",
            defaults: new { controller = "Foo", action = "Index", myid = UrlParameter.Optional },
            namespaces: new[] { "MyApp.Controllers" }
        );

        routes.MapRoute(
            name: "Default",
            url: "{controller}/{action}/{id}",
            defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional },
            namespaces: new[] { "MyApp.Controllers" }
        );

And my FooController action method

 public ActionResult Index(int MyID)
    {
        //...
   return View();
    }

If I add the myid parameter to the querystring things work fine (i.e. /Foo/Index/?myid=1). But the rewritten url (/Foo/Index/1) results in this error:

The parameters dictionary contains a null entry for parameter 'MyID' of non-nullable type 'System.Int32' for method 'System.Web.Mvc.ActionResult Index(Int32)' in 'TPC_CS_Portal.Controllers.FooController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter.
Parameter name: parameters

As mentioned, my other controllers that use the default route (with id parameter) all work fine (e.g. /SomethingElse/Index/1).

What do I need to do to get my custom route working?

Upvotes: 0

Views: 43

Answers (1)

user806982
user806982

Reputation: 135

The problem here was that there was a separate MapRoute defined elsewhere against the FooController:

routes.MapRoute(
        name: "MyOtherCustomRoute",
        url: "Foo/Index/{param1}/{param2}",
        defaults: new { controller = "Foo", action = "Index", param1 = UrlParameter.Optional, param2 = UrlParameter.Optional },
        namespaces: new[] { "MyApp.Controllers" }
    );

This was taking precedence (matching against the requested url), so I moved things around so that it appears after MyCustomRoute.

Upvotes: 1

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