我一直在寻找相同的问题，并且似乎没有Windows身份验证事件，即使Authenticate事件对于表单和Windows也很常见.

I was looking at the same issue, and looks like there is no events for windows authentication, even that Authenticate event is common for forms and windows.

但是我找到了解决方案！

But I found a solution to this!

http://www.codeproject.com/Articles/11202/Redirecting-to-custom-401-page-when-quot-Access-de

更新

摘自原始文章

protected void Application_EndRequest(Object sender, EventArgs e)
{ 
 HttpContext context = HttpContext.Current;
 if (context.Response.Status.Substring(0,3).Equals("401"))
 {
    if(User.Identity.IsAuthenticated)
    {
        // this means user is authenticated, but 401 still returned
        // which means no access to page or whatever you are trying to access?
    }
 } 
}

UPDATE2

我还发现该解决方案并非在所有情况下都有效.我在不同的环境中进行测试，因此为我工作，但为其他人工作.

I also found out that this solution doesn't work in all cases. I was testing in different environments, so was working for me, but not for others.

默认情况下，IIS甚至不会运行这段代码，只是返回它自己的错误页面，您要做的就是告诉IIS让应用程序处理错误.

By default IIS will not even run this piece of code and just return it's own error page, what you want to do is tell IIS to let app handle errors.

<httpErrors existingResponse="PassThrough">
</httpErrors>

现在，这样说来，IIS将不再返回任何自定义错误，您将需要在应用程序中处理它们，即.不仅是401，还有403、405等

Now, with that said, IIS won't return any more of custom errors and you will need to handle them in application, ie. not only 401, but 403, 405, etc