angularjs – $http：如何使用CORS从WebApi获取头文件名

HTTP/1.1 200 OK
Content-Length: 121257
Content-Type: application/pdf
Server: Microsoft-HTTPAPI/2.0
Access-Control-Allow-Origin: *
Access-Control-Expose-Headers: *
Content-Disposition: attachment; filename=Order-414.pdf
Date: Wed,11 Feb 2015 05:32:25 GMT

我只想在下载时获取文件名(Order-414.pdf)作为pdf名称.但是在这个代码块中：

$http.get(httpPath,{ responseType: 'arraybuffer' })
            .success(function (data,status,headers) {
                debugger;
                // just return content-type
                var header = headers();

header对象只包含content-type.

Object {content-type: "application/pdf"}

我在某处读到我们需要为WebAPI配置CORS：

private static void RegisterCorsConfig(HttpConfiguration config)
    {
        var cors = new EnableCorsAttribute("*","*","*");
        //var cors = new EnableCorsAttribute("*","DataServiceVersion,MaxDataServiceVersion");
        //cors.ExposedHeaders.Add("*");
        //cors.ExposedHeaders.Add("filename");
        config.EnableCors(cors);
    }

但它仍然无效.请帮我.
提前致谢.