//取出文章分类，和分类相应的10篇文章

            var query = from t1 in context.Category                        

                        select new

                        {

                            Category,//分类

                            Article = (from t2 in context.Article//文章

                                       orderby t2.ModifiedDate descending

                                       where t2.Category.CategoryID == t1.CategoryID

                                       select new Article { ArticleID = t2.ArticleID, Title = t2.Title }).Take(10)

                                        //如果 new Article { ArticleID = t2.ArticleID, Title = t2.Title } 改成

                                       //select t2 就是正常的，但我不只想取出标题和ID，不想全部取出（性能低）



                        };



            var CategoryList = new List<Category>();

            if (query != null)

            {

                foreach (var i in query)//这里出错

                {



                    foreach (var j in i.Article)

                    {



                        i.Category.Article.Attach(j);//给分类的Article集合属性 Attach 文章



                    }