我得到这个问题后运行选择IQueryable

“$project或$group不支持{document}。”

public Interface IVideo
{
   ....
   public string File { get; set;} 
   public bool Categorized { get; set;}
   public IMovie Movie { get; set;} 
   ....
}

public Interface IMovie
{
   ....
   public List<string> Langauge {get; set;} 
   ....
}

public static Dictionary<string, int> GetLanguage(string isp)
{
    //Repository.GetVideos() is IQueryable<IVideo>
    var videos = Repository.GetVideos().Where(q => q.Categorized && (
                                                       q.File == isp ||
                                                       q.File == "st"));

    var language = videos.SelectMany(q => q.Movie.Language).Select(e => e);
    var ql = from x in language
        group x by x
        into g
        let count = g.Count()
        orderby count descending
        select new {g.Key, count}; // issue is here

    return ql.ToDictionary(item => item.Key, item => item.count);
}

如何解决此问题？