Question

I have an ASP.Net application which has an area called ‘Customers’. This area has a controller with the same name with a single method called Index.

I have the following route defined:

context.MapRoute(null,
    "Customers/{controller}/{action}",
    new { controller = "customers", action = "Index" }
);

This allows my to navigate to use the following URL to navigate to the index method on my Customers controller.

MyDomain/Customers

In my customer area I also have another controller called products. This has a number of methods that allow me to work with product entities (mostly auto-generated by Visual Studio at the moment).

With my current route I can navigate to the products controller using URL’s like this:

MyDomain/Customers/Products (shows the index page of the products
controller) MyDomain/Customers/Products/Create (Shows a page to add
new products). MyDomain/Customers/Products/Details?id=1234 (Show the
product with the id of 1234)

Now what I want to be able to do is navigate to the details page with a much more user friendly URL such as:

MyDomain/Customers/Products/1234

I have defined a new route that look like this:

context.MapRoute(null,
    "Customers/Products/{id}",
    new { controller = "Products", action = "Details" }
    );

The route is defined before the first route I demonstrated.
This allows me to navigate to the products page as I want, however I can no longer navigate to other methods on my products controller.

E.G. The following URL

MyDomain/Customers/Products/Create

Gives me the following error:

The parameters dictionary contains a null entry for parameter ‘id’ of
non-nullable type ‘System.Int32’ for method ‘System.Web.Mvc.ViewResult
Details(Int32)’

If I change the order of the routes then I can navigate to all the methods on my products controller but my details URL reverts to the old format of having a query parameter.

If I update the route to look like this:

context.MapRoute(null,
    "Customers/Products/{id}",
    new { controller = "Products", action = "Details", id = UrlParameter.Optional }
    );

Then I still get the same problem.

Can anyone tell me how to structure my routes to get the result I want? In summary:

1. If I navigate to the Customers area I want my URL to look like ‘MyDomain/Customers’
2. If I navigate to the product details page I want my URL to look like “MyDomain/Customers/Products/1234”.
3. If I navigate to any other product page I want my URL to look like ‘MyDomain/Customers/Products/Create’

Answer 1

If the ID is always going to be an int then you can add a constraint to the route like this:

context.MapRoute(null,
                 "Customers/Products/{id}",
                 new {controller = "Products", action = "Details", id = UrlParameter.Optional},
                 new {id = @"\d+"} // Constraint to only allow numbers
                );