我不应该将Linq to SQL实体表强制转换为它的实际类型吗?

当我从页面加载方法调用“f_categorynewsget”函数时,我得到的是空值。但我可以看到tblnewsler对象在返回行之前已经充满了对象。

protected void Page_Load(object sender, EventArgs e)
{
    var tblNewsler = News.f_CategoriNewsGet("ÇEVRE", 18); // return object is always
    Table<News> tblNewsler1 = tblNews;
    rptNatureNews.DataSource = tblNews != null ? tblNews.Take(6) : null;
    rptNatureNews.DataBind();
}

static public Table<News> f_CategoriNewsGet(string _sCategoriName, int _iTop)
{
    var tblNews = (from news in DAO.context.GetTable<News>()
                       join kategori in DAO.context.GetTable<NewsCategori>() on                                news.M_RefNewsCategoriId equals kategori.M_NewsCategoriId
                       where kategori.M_Adi.Equals(_sCategoriName)
                       orderby news.M_InsertDate descending
                       select news).Take(_iTop);
    return tblNews as Table<News>;
}