asp.net mvc routing rules

Question

I have the following routes defined in an asp.net mvc project

//Products/Category/SubCategory/Page 
routes.MapRoute(
    "ProductCategoryTypePaging", 
    "Products/{Category}/{subCategory}/Page{page}", 
    new { controller = "Products", action = "Index" }, new { page = @"\d+" }
);

//Products/Category/Page 
routes.MapRoute(
    "ProductCategoryPaging", 
    "Products/{Category}/Page{page}", 
    new { controller = "Products", action = "Index" }, new { page = @"\d+" }
);

//Products/Category/SubCategory 
routes.MapRoute(
    "ProductCategoryType", 
    "Products/{Category}/{subCategory}", 
    new { controller = "Products", action = "Index", page = 1 }
);

//Products/Category 
routes.MapRoute(
    "ProductCategory", 
    "Products/{Category}", 
    new { controller = "Products", action = "Index" }
);


routes.MapRoute(
    "Default", // Route name
    "{controller}/{action}/{id}", // URL with parameters
    new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults
);

These seem to work fine BUT if i try and view product details, it breaks. To view details, the Url is like this:

/Products/Details/18

Running that matches on the Products/Category/SubCategory route

What do i need to do differently to make this work?

Answer 1

There are a number of ways to do this:

1. Change the static parts of the route to be different, such as changing the Products/Category/SubCategory route to have the following template (or something similarly unique): "ProductCategory/{Category}/{subCategory}"
2. Add a constraint to that same route that allows only valid categories, and allows things that aren't categories to pass through.

The fundamental problem is that the route structure in this app is ambiguous. What would you expect to happen if there was a category called "Details" that had a sub-category called "18"? Which route should it map?

In the vein of option #2 I list above, the constraint you could add to the category/subcategory route would be for example a RegEx constraint that disallows the category name to be "Details". That will cause the route to be skipped, but it will also prevent the app from ever having a category called "Details". If that's OK for the app, it should work just fine.