Best way to implement a 404 in ASP.NET

Question

I\'m trying to determine the best way to implement a 404 page in a standard ASP.NET web application. I currently catch 404 errors in the Application_Error event in the Glob

Answer 1

I think the best way is to use the custom errors construct in your web.config like below, this let's you wire up pages to handle all of the different HTTP codes in a simple effective manner.

  <customErrors mode="On" defaultRedirect="~/500.aspx">
     <error statusCode="404" redirect="~/404.aspx" />
     <error statusCode="500" redirect="~/500.aspx" />
  </customErrors>

Answer 2

I also faced with 302 instead 404. I managed to fix it by doing the following:

Controller:

public ViewResult Display404NotFoundPage()
        {
            Response.StatusCode = 404;  // this line fixed it.

            return View();
        }

View:

Show some error message to user.

web.config:

<customErrors mode="On"  redirectMode="ResponseRedirect">
      <error statusCode="404" redirect="~/404NotFound/" />
</customErrors>

Lastly, the RouthConfig:

routes.MapRoute(
             name: "ErrorPage",
             url: "404NotFound/",
             defaults: new { controller = "Pages", action = "Display404NotFoundPage" }
         );

Answer 3

I can see that setting up the 404 page in the web.config is a nice clean method, BUT it still initially responds with a 302 redirect to the error page. As an example, if you navigate to:

https://stackoverflow.com/x.aspx

you'll be redirected via a 302 redirect to:

https://stackoverflow.com/404?aspxerrorpath=/x.aspx

What I want to happen is this:

http://www.cnn.com/x.aspx

There's no redirect. A request for the missing URL returns a 404 status code with a friendly error message.

Answer 4

You can use the web.config to send 404 errors to a custom page.

    <customErrors mode="RemoteOnly" defaultRedirect="GenericErrorPage.htm">
        <error statusCode="403" redirect="NoAccess.htm" />
        <error statusCode="404" redirect="FileNotFound.htm" />
    </customErrors>

Answer 5

I really like this approach: it creates a single view to handle all error types and overrides IIS.

[1]: Remove all 'customErrors' & 'httpErrors' from Web.config

[2]: Check 'App_Start/FilterConfig.cs' looks like this:

public class FilterConfig
{
    public static void RegisterGlobalFilters(GlobalFilterCollection filters)
    {
        filters.Add(new HandleErrorAttribute());
    }
}

[3]: in 'Global.asax' add this method:

public void Application_Error(Object sender, EventArgs e)
{
    Exception exception = Server.GetLastError();
    Server.ClearError();

    var routeData = new RouteData();
    routeData.Values.Add("controller", "ErrorPage");
    routeData.Values.Add("action", "Error");
    routeData.Values.Add("exception", exception);

    if (exception.GetType() == typeof(HttpException))
    {
        routeData.Values.Add("statusCode", ((HttpException)exception).GetHttpCode());
    }
    else
    {
        routeData.Values.Add("statusCode", 500);
    }

    Response.TrySkipIisCustomErrors = true;
    IController controller = new ErrorPageController();
    controller.Execute(new RequestContext(new HttpContextWrapper(Context), routeData));
    Response.End();
}

[4]: Add 'Controllers/ErrorPageController.cs'

public class ErrorPageController : Controller
{
    public ActionResult Error(int statusCode, Exception exception)
    {
        Response.StatusCode = statusCode;
        ViewBag.StatusCode = statusCode + " Error";
        return View();
    }
}

[5]: in 'Views/Shared/Error.cshtml'

@model System.Web.Mvc.HandleErrorInfo
@{
    ViewBag.Title = (!String.IsNullOrEmpty(ViewBag.StatusCode)) ? ViewBag.StatusCode : "500 Error";
}

 <h1 class="error">@(!String.IsNullOrEmpty(ViewBag.StatusCode) ? ViewBag.StatusCode : "500 Error"):</h1>


//@Model.ActionName
//@Model.ContollerName
//@Model.Exception.Message
//@Model.Exception.StackTrace

:D

Answer 6

Easiest answer: don't do it in code, but configure IIS instead.