Question

简明扼要的问题:鉴于以下特有物体,鉴于主要关键因素,你如何更新最深的特有财产?

public class Recipe {
    public int RecipeID {get;set;}     // PK

    public string name {get;set;}
    public IList<RecipeStep> RecipeSteps {get;set;}
}

public class RecipeStep {
    public int RecipeID {get;set;}     // PK
    public int RecipeStepID {get;set;} // PK

    public string name {get;set;}
    public IList<Ingredient> {get;set;}
}

public class Ingredient {
    public int RecipeID {get;set;}     // PK
    public int RecipeStepID {get;set;} // PK
    public int IngredientID {get;set;} // PK

    public string name {get;set;}
}

因此,我如何确定收款人。 RecipeStep.Ingredient.name given that RecipeID = 2, RecipeStepID = 14, and IngredientID = 5 ( which are the Value of the int, not the index). 希望能有一些直接的办法,在没有住所的情况下提及这些物品。 Linq 言论是罚款。 (当我尝试Linq时,我最后修改了价值的副本,而不是价值本身。) LOL。

Answer 1

Ingredient theIngredient =
(
  from r in Recipes
  where r.RecipeId == 2
  from rs in r.RecipeSteps
  where rs.RecipeStepID == 14
  from ing in rs.Ingredients
  where ing.IngredientId == 5
  select ing
).Single()

theIngredient.name = theName;

Answer 2

你们重新寻找选择,可以采取多种深度的计算方法,将其整理成一个可计算数的、能够获取所有成分的单一组合结果,然后在什么地方()满足你们的条件。

Ingredient ing = theRecipe.RecipeSteps.SelectMany((recipeStep) => recipeStep.Ingredient)
    .FirstOrDefault((ingredient) =>
        ingredient.RecipeId == 2 &&
        ingredient.RecipeStepId == 14 &&
        ingredient.IngredientId == 5);

ing.name = "pretty flowers";

Answer 3

Linq query:

Ingredient ing = theRecipe.RecipeSteps.Ingredients
    .FirstOrDefault(i =>
        i.RecipeId == 2 &&
        i.RecipeStepId == 14 &&
        i.IngredientId == 5);

if (ing != null) ing.name = "New Name";

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