asp.net-mvc – 即使我设置CustomError =“On”,自定义错误页面

我正在使用Visual Studio 2012和MVC 4 Framework,如果未处理异常,我希望看到共享文件夹的友好错误页面. (我知道,作为一个开发者,我需要查看错误详细信息,但我只想测试此设置)
到目前为止,我知道在web.config的system.web部分添加以下代码应该可以解决问题

<customErrors mode="On" />

不幸的是,我得到了这个：

Server Error in ‘/’ Application.

Runtime Error Description: An application error occurred on the
server. The current custom error settings for this application prevent
the details of the application error from being viewed.

Details: To enable the details of this specific error message to be
viewable on the local server machine,please create a
tag within a “web.config” configuration file located in the root
directory of the current web application. This tag
should then have its “mode” attribute set to “RemoteOnly”. To enable
the details to be viewable on remote machines,please set “mode” to
“Off”.

<!-- Web.Config Configuration File -->

 <configuration>
     <system.web>
         <customErrors mode="RemoteOnly"/>
     </system.web> </configuration>

Notes: The current error page you are seeing can be replaced by a
custom error page by modifying the “defaultRedirect” attribute of the
application’s configuration tag to point to a custom
error page URL.

<!-- Web.Config Configuration File -->

 <configuration>
     <system.web>
         <customErrors mode="On" defaultRedirect="mycustompage.htm"/>
     </system.web> </configuration>

我想按照描述执行此操作,而不是使用向HomeController添加操作,设置路由或其他内容的解决方法.
这应该起作用的参考如下：
http://pluralsight.com/training/players/PSODPlayer?author=scott-allen&name=mvc3-building-controllers&mode=live&clip=0&course=aspdotnet-mvc3-intro
(在左侧选择“动作过滤器”一章并跳至分钟3:30)

更新(链接已更改)：
http://pluralsight.com/training/Player?author=scott-allen&name=mvc4-building-m2-controllers&mode=live&clip=0&course=mvc4-building
(在顶部单击描述“ASP.NET MVC 4中的Controller”的细线,然后单击“Action Filters”并跳到分钟5:00)

有没有人知道为什么我看不到上面提到的设置的友好错误页面？
提前致谢！

<system.web>

    <customErrors mode="On"></customErrors>

</system.web>

[HandleError]
public class HomeController : Controller
{
    public ActionResult Index()
    {
    throw new Exception("Error Occured !");
    ViewBag.Message = "Welcome to ASP.NET MVC!";

    return View();
    }

    public ActionResult About()
    {
    return View();
    }
}

@model System.Web.Mvc.HandleErrorInfo

@{
    ViewBag.Title = "Error";
}

<h2>
    Sorry,an error occurred while processing your request.
</h2>