使用ASP.NET MVC，我可以使用jQuery GET和FilePathResult下载文件吗?

我的应用程序需要在文件被缓存后下载文件，然后再下载文件.我有一个jQuery.post()缓存文件，然后在文件成功缓存后调用以下命令:

My app needs to download a file after the file has been cached and then download the file. I have one jQuery.post() cache the file and then call the following after the file is successfully cached:

<script type="text/javascript">
    function startViewingFiles(fileNames) {
        $.get(
            '<%= Url.Action(MvcTemplates.Document.DisplayDownload()) %>',
            { fileName: fileNames[0] },
            function() {
                $('<div class="status fill"><p>Download complete</p></div>')
                    .appendTo('#ViewerContainer')
                    .fadeIn('slow'); 
            }
        );
    }
</script>

这与以下操作通信，因为我观察到调用实际上是在VS 2008中到达服务器的，并且FilePathResult成功退出了该方法:

This communicates with the following action, as I have observed the calls actually make it to the server in VS 2008 and the FilePathResult exits the method successfully:

[HttpGet]
public virtual ActionResult DisplayDownload(string fileName)
{
    var path = _CacheService.GetCachedPath(fileName);
    return new FilePathResult(path, _MimeDictionary.LookupMimeType(fileName));
}

使用Firebug，我看到响应包含一个"500 Internal Server Error"，其中抱怨System.UnauthorizedAccessException: Access to the path 'C:\websites\WebSubscriptionPortal\CacheLocation' is denied.我将VS开发服务器和IIS 7.5中的Web应用程序都配置为以我的用户身份运行，并具有对目录的完全访问权限，但我总是会收到此错误.当我拥有视图输出WindowsIdentity.GetCurrent().Name时，无论我使用哪个服务器，它都会输出我的用户名.

Using Firebug, I see the response contains a "500 Internal Server Error" that complains of a System.UnauthorizedAccessException: Access to the path 'C:\websites\WebSubscriptionPortal\CacheLocation' is denied. I configured both the VS development server and the web app in IIS 7.5 to run as my user with full access to the directory, but I always get this error. When I have the view output WindowsIdentity.GetCurrent().Name, it outputs my user name regardless of which server I use.

1. 我为什么要得到UnauthorizedAccessException?
2. 显然，我不能使用jQuery通过FilePathResult下载文件.这是真的?
3. 我是否需要更改客户端或服务器上的ActionResult所使用的方法以通过Javascript方法开始下载?

1. Why am I getting the UnauthorizedAccessException?
2. Apparently, I cannot use jQuery to download a file using FilePathResult. Is this true?
3. Do I need to change the method used on the client or the ActionResult on the server to start the download via a Javascript method?

更新:UnauthorizedAccessException异常是由于fileNames参数为null的事实，因为未设置任何路由来映射到名为"fileNames"的方法.因此，FilePathResult构造函数的path参数只是目录名称，如异常消息中所示.

Update: The UnauthorizedAccessException exception is due the fact that the fileNames parameter is null, as no route was setup to map to a method with a parameter named "fileNames". So the path parameter to the FilePathResult constructor is simply the directory name as shown in the exception message.