Linq多对多查询

Linq多对多查询求救
我这个需求是多对多  菜品和菜品分类 要根据菜品分类 查出所有菜品信息（包括菜品分类） 就是确定一条分类然后还要再加到查出每个菜品所有分类（这里的分类不止一个）代码如下：

var q = db.foodcategories.First(fc => fc.Id == categoryId);


             var q_a = from qq in q.foods

                       from p in db.pictures

                       //from qfc in q_fc

                       where p.FoodId==qq.Id

                       select new FoodModel

                       {

                           Id = qq.Id,

                           Name = qq.Name,

                           pictureUrl=p.Url,

                           Price = qq.Price,

                           Description = qq.Description,

                           MainIngredient = qq.MainIngredient,

                           MinorIngredient = qq.MinorIngredient,

                           Flavoring = qq.Flavoring,

                           Discount = qq.Discount,

                           Recommended = qq.Recommended