Can Asp.Net Mvc Route Constraints throw a 404 instead of InvalidOperationException? - asp.net-mvc

Question

I'm trying to use route constraints in an Asp.Net MVC Application.
routes.MapRoute(
"theRoute",
"MyAction/{page}",
new { controller = "TheController", action = "MyAction", page = 1 },
new { page = #"[0-9]" });
When I enter an url like ~/MyAction/aString, an YSOD is shown with an invalid operation exception. What can I do to redirect invalid url to the 404 page?
I know I can solve the issue with a string parameter in the controller action and int.TryParse, but then the route constaint is useless.
How can I choose the exceptiontype that is thrown by the route constraints?

Answer 1

The problem is that you do not have a route that matches the route that ends in a string.
Modify your routes similar to:
routes.MapRoute(
"Default", // Route name
"{controller}/{action}/{id}", // URL with parameters
new { controller = "Home", action = "Index", id = 0 },
new { id = "[0-9]" }// Parameter defaults
);
routes.MapRoute(
"Default2", // Route name
"{controller}/{action2}/{sid}", // URL with parameters
new { controller = "Home", action = "Index2", sid = "" } // Parameter defaults
);
and modify your controller
public ActionResult Index(int id)
{
ViewData["Title"] = "Home Page";
ViewData["Message"] = "Welcome to ASP.NET MVC! Your id is: "+ id.ToString();
return View();
}
public ActionResult Index2(string sid)
{
ViewData["Title"] = "Home Page 2."+sid.ToString();
ViewData["Message"] = "Welcome to ASP.NET MVC! \"" + sid.ToString() +"\" is an invalid id";
return View("index");
}
now when you pass a string for the ID, Index2 will be called and you can do whatever you need to do to handle the incorrect parameter.

Answer 2

Just to mention a more general redirection:
You can write in the Web.config of your application:
<system.web>
...
...
<customErrors mode="On">
<error
statusCode="404"
redirect="/Home/MyCustomError" />
<!-- Is not necessary that the
view MyCustomError.aspx are inside the
Home folder, you can put that
view in the Shared folder.
-->
</customErrors>
...
...
</system.web>
Then you need to have an ActionResult called MyCustomError
public class HomeController : Controller
{
...
...
public ActionResult MyCustomError(string aspxerrorpath)
/* the var aspxerrorpath
* is that MVC generated by
* default */
{
ViewData["messageError"] = aspxerrorpath;
return View();
}
}
Then you can make a custom error page:
<%# Page Language="C#"
MasterPageFile="~/Views/Shared/Site.Master"
Inherits="System.Web.Mvc.ViewPage<System.Web.Mvc.HandleErrorInfo>" %>
<asp:Content ID="errorTitle" ContentPlaceHolderID="TitleContent" runat="server">
Error
</asp:Content>
<asp:Content ID="errorContent" ContentPlaceHolderID="MainContent" runat="server">
<h2>Shit happends</h2>
<p> <%: ViewData["messageError"]%></p>
<p>aaaaaaaaaaaaaaa!!!!!!!!!!!!!!!!!!!!</p>
</asp:Content>