sql - Linq 看不到属性

Question

我有以下类，我正在尝试从不同的相关类访问它的属性，如下所示:

var nuInfo = recipe.RECIPE_INGREDIENT
    .Select(i => i.INGREDIENT.INGREDIENT_NUTRITIONAL_INFO)
    .Where(ni => ni.NUTRITIONAL_INFO.Main == 1);

但是，我无法访问 INGREDIENT_NUTRITIONAL_INFO 的任何(虚拟或非虚拟)属性。

INGREDIENT_NUTRITIONAL_INFO类如下:

 public class INGREDIENT_NUTRITIONAL_INFO
 {
     public int IngredientId { get; set; }
     public int Nutritional_InfoId { get; set; }
     public double Amount { get; set; }
     public DateTime DateSubmitted { get; set; }
     public DateTime DateModified { get; set; }
     public string SubmittedBy { get; set; }
     public string ModifiedBy { get; set; }

     public virtual AspNetUsers AspNetUsers { get; set; }
     public virtual AspNetUsers AspNetUsers1 { get; set; }
     public virtual INGREDIENT INGREDIENT { get; set; }
     public virtual NUTRITIONAL_INFO NUTRITIONAL_INFO { get; set; }
}

错误代码如下:

CS1061 'ICollection' does not contain a definition for 'NUTRITIONAL_INFO' and no extension method 'NUTRITIONAL_INFO' accepting a first argument of type 'ICollection' could be found (are you missing a using directive or an assembly reference?)

我在 Linq 中遗漏了什么吗？我是否试图遍历太多关系？

Answer 1

错误是因为您没有在查询末尾添加 .First() 或 .FirstOrDefault():

var nuInfo = recipe.RECIPE_INGREDIENT.Select(i => i.INGREDIENT.INGREDIENT_NUTRITIONAL_INFO)
.Where(ni => ni.NUTRITIONAL_INFO.Main == 1)

您的代码正在尝试将 NUTRITIONAL_INFO 作为集合的属性进行访问，而不是作为集合中成员的属性进行访问。