How to return 'own' 404 custom page?

Question

In case if error occurred on my web site I do the following:

        Server.Transfer("/error.aspx");

and that page has code:

protected void Page_Load(object sender, EventArgs e)
{
    ...

    Response.StatusCode = 404;
}

If I work on the localhost then together with 404 status returned for the page, page displays 'proper error description'.

Once I published the same code to the internet all pages with errors are still displayed with 404 status code, but the don't have the content. Instead, they have the standard 404 error message:

404 - File or directory not found.

if the line "Response.StatusCode = 404" commented out then the proper page is provided, but it has 200 status code.

Question: how to return user-friendly error page that in the same time has 404 error status code?

Any thoughts are welcome! Thanks a lot in advance!

P.S. ASP.NET 4.0

Answer 1

<httpErrors errorMode="Custom">
     <remove statusCode="404"/>
     <error statusCode="404" path="ErrorPages/error404.htm" responseMode="Redirect"/>
  </httpErrors>

This works for me if I don't use the tilde (~) in the path attribute

Answer 2

A ha!

Try this:

Response.TrySkipIisCustomErrors = true;
Response.Status = "404 Not Found";
Response.StatusCode = 404;

I found as soon as I added Response.TrySkipIisCustomErrors=true before setting the status code, I would see the normal page copy AND a 404 is returned. Without this line the standard IIS 404 page is displayed.

Alternatively, this can be set in the web.config like so:

<system.webServer>
    <httpErrors existingResponse="PassThrough">
        // custom error page mappings
    </httpErrors>
</system.webServer>

The key thing here is existingResponse="PassThrough"

This was added to IIS7 thus is required on sites running in Integrated Pipeline mode.

For more info: http://msdn.microsoft.com/en-us/library/system.web.httpresponse.tryskipiiscustomerrors.aspx

Update Updating for clarrification/more info as people are still finding this useful. It's worth noting that if you need a simple, generic 404 page use the web.config method (and best make it a plain HTML page).

The method I describe works best if you have a heavily dynamic or CMS driven site where any given page could potentially return a 404 but you want to show your visitor related info.

For example, a special offers page (offers/some-offer) could do a lookup for the offer (some-offer) and if it doesn't exist show alternative or related offers while returning a 404 under the bonnet. As far as the visitor is aware they've just been told the offer is no longer available but they're still in the offers section but we're also telling robots to un-index the URL. This would be a lot harder to do if there was just one generic 404 page.

Answer 3

Combining Jag's and adt's answers, I still had a problem. When a 404 was handled by the static file handler (as opposed to ASP.NET), I got a blank response. (The status was correctly 404.)

To fix it, I had to add errorMode="Custom" to the <httpErrors> element. If your error page uses ASP.NET, you need to include responseMode="ExecuteURL".

<system.web>
    <customErrors mode="On" defaultRedirect="~/Error.aspx" redirectMode="ResponseRewrite" />
</system.web>

<system.webServer>
    <httpErrors errorMode="Custom">
        <remove statusCode="404" />
        <error statusCode="404" path="/Error.aspx" responseMode="ExecuteURL" />
    </httpErrors>
</system.webServer>

Answer 4

<customErrors mode="On" defaultRedirect="~/Error/GenericErrorPage.aspx">

     <error statusCode="404" redirect="~/Error/404.aspx" />

</customErrors>

http://msdn.microsoft.com/en-us/library/h0hfz6fc(v=vs.71).aspx

http://msdn.microsoft.com/en-us/library/aa479319.aspx

Answer 5

To show your own page with the correct 404 statuscode, you can use the following code:

1) In your web.config add the following:

<customErrors mode="On" redirectMode="ResponseRewrite">
  <error statusCode="404" redirect="404.htm" />
</customErrors>

and:

<httpErrors errorMode="Custom">
  <remove statusCode="404"/>
  <error statusCode="404" path="404.htm" responseMode="File"/>
</httpErrors>

2) Add a 404.htm file to the root of your website:

<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <title>404 - Not Found</title>
    <meta http-equiv="refresh" content="5;url=/404-PAGE" />
  </head>
  <body>
       CONTENT
  </body>
</html>

You can either add content to the body of this file and remove the META refresh or simply use the META refresh to open a page within your CMS.

Answer 6

You can achieve this by configuring your web.config file. Please check the link below to an article, which explains at the bottom of the page, how to display different custom error pages for different HTTP error statuses.

• Displaying a Custom Error Page