小编Ben*_*Ben的帖子

我有一个LINQ to EF查询,它以类的形式返回数据.该类有一个List<RecipeCategories>我需要填充的属性.RecipeCategories表是Recipe表和RecipeCategories表之间的关系表,可以是多对多.我找到了足够的信息来编译代码,但是它在运行时出错并且我无法弄清楚如何正确地进行编译.

ri = (from r in recipeData.Recipes
              where r.ID == recipeId
              select new RecipeItem
              {
                  Id = r.ID,
                  ProductId = r.Product.ID,
                  RecipeName = r.recipeName,
                  RecipeDescription = r.recipeDescription,
                  Servings = r.servings.HasValue ? r.servings.Value : 0,
                  CreatedDate = r.createdDate,
                  PrepTime = r.prepTime.HasValue ? r.servings.Value : 0,
                  CookTime = r.cookTime.HasValue ? r.servings.Value : 0,
                  Approved = r.approved,
                  RecipeInstructions = r.recipeInstructions,
                  RecipeIngredients = r.recipeIngredients,
                  RecipeCategories = r.RecipeCategories.Select(i => new RecipeCategoryItem { Id = i.ID, CategoryName = i.categoryName }).ToList()
              }).First();

这是我得到的错误. …