Add the following content in web. config:
<System. web>
<CustomErrors mode = "On" redirectMode = "ResponseRewrite"> <! -It must be ResponseRewrite; otherwise, the HTTP header returns HTTPStatusCode or 302->
<Error statusCode = "404" redirect = "/FileNotFound. aspx"/> <! -It must be An aspx file. Although the html file can also be used, the returned StatusCode is 302, and aspx is used to modify the HTTPStatusCode to 404->
</CustomErrors>
</System. web>
Then, create the file FileNotFound. aspx in the root directory of the webpage (according to the file directory indicated by redirect above). The content is as follows:
<% @ Page Language = "C #" Inherits = "System. Web. UI. Page" %>
<Script runat = "server">
Protected void Page_Load (object sender, EventArgs e)
{
If (! IsPostBack)
{
Response. Status = "404 No Found"; // rewrite StatusCode to 404
}
}
</Script>
<! -The following HTML code can be replaced with the HTML code you want to customize the 404 page->
<! DOCTYPE html PUBLIC "-// W3C // dtd xhtml 1.0 Transitional // EN" "http://www.w3.org/tr/xhtml1/dtd/xhtml1-transitional.dtd">
<Html xmlns = "http://www.w3.org/5o/xhtml">
<Head id = "Head1" runat = "server">
<Title> the page does not exist. </title>
</Head>
<Body>
The page does not exist! <A href = "http://www.yourdomain.com"> Click Back </a>
</Body>
</Html>
