ASP.net MVC5 - For 循环发布单个项目但不是集合

Question

我正在创建一个新的食谱输入表单，我发现了两个有趣的问题：

1. 成分不会发布到配方集合中，并且
2. 当我将参数设置为集合时，表单只会发布一个成分并发送 null。

理想情况下，我希望成分集合位于配方项下，但我会满足于让成分集合写入参数。

以下是两个模型（由实体框架生成）：

食谱：

    public int recipeId { get; set; }

    [Required]
    [StringLength(255)]
    [DisplayName("Name")]
    public string name { get; set; }

    [DisplayName("Category")]
    public int? mealCategoryId { get; set; }

    [DisplayName("Preperation Time")]
    public int? prepTime { get; set; }

    [DisplayName("Cook Time")]
    public int? cookTime { get; set; }

    [DisplayName("Stand Time")]
    public int? standTime { get; set; }

    [DisplayName("Serving Size")]
    public int? servingSize { get; set; }

    [DisplayName("Status")]
    public int recipeStatusId { get; set; }

    [DisplayName("Description")]
    [UIHint("Multiline")]
    public string description { get; set; }

    public virtual ICollection<Direction> Directions { get; set; }

    public virtual ICollection<Image> Images { get; set; }

    public virtual ICollection<Ingredient> Ingredients { get; set; }

    public virtual MealCategory MealCategory { get; set; }

    public virtual ICollection<Nutrition> Nutritions { get; set; }

    public virtual ICollection<Rating> Ratings { get; set; }

    public virtual RecipeStatus RecipeStatus { get; set; }
}

成分：

public partial class Ingredient
    {
        public int ingredientId { get; set; }

        public int? recipeId { get; set; }

        public int? subCategoryId { get; set; }

        public int measurementId { get; set; }

        public int amount { get; set; }

        public virtual Recipe Recipe { get; set; }

        public virtual SubCategory SubCategory { get; set; }

        public virtual Measurement Measurement { get; set; }

    }

查看代码：

   <div class="form-horizontal">
        <h4>Ingredients</h4>
        <hr />
        <table class="table IngredientList">
            <tr>
                <th>
                    @Html.LabelFor(model => model.Recipe.Ingredients)
                </th>
                <th>
                    @Html.LabelFor(model => model.SelectedMeasurementId)
                </th>
                <th>
                    @Html.Label("Amount")
                </th>
            </tr>

            @for (int i = 0; i < Model.Recipe.Ingredients.Count; i++)
            {
                <tr>
                    <td>
                        @Html.DropDownListFor(m => Model.Recipe.Ingredients.ElementAt(i).ingredientId, Model.SubIngredients, new { @class = "form-control input-block-level" })
                    </td>
                    <td>
                        @Html.DropDownListFor(m => Model.Recipe.Ingredients.ElementAt(i).measurementId, Model.Measurements, new { @class = "form-control input-block-level" })
                    </td>
                    <td>
                        @Html.TextBoxFor(m => Model.Recipe.Ingredients.ElementAt(i).amount, new { @class = "form-control input-block-level" })
                    </td>
                </tr>
            }

        </table>
</div>

控制器：

   [HttpPost]
    [ValidateAntiForgeryToken]
    public ActionResult Create(Recipe recipe, int SelectedCategoryId, List<Ingredient> Ingredients)

    {
        recipe.mealCategoryId = SelectedCategoryId;
        recipe.recipeStatusId = 1;

        if (ModelState.IsValid)
        {
            dbContext.Entry(recipe).State = EntityState.Added;
            dbContext.SaveChanges();
            return RedirectToAction("Details", new {id = recipe.recipeId});
        }

        return View(recipe);
    }

因此，如果我将参数设置为 List Ingredients，则返回 null。如果我将其设置为成分成分，那么我只会得到四种成分中的第一种。 （我将模型设置为在加载时创建 4 个成分记录。）

我的问题是：如何让它通过成分集合？

编辑：

我已确认请求将所有 4 种成分发送过来。绑定好像有问题。

Answer 1

创建自己的 ViewModel 来保存数据，不要使用实体框架预生成的类进行模型绑定。这是概念证明的一个非常基本的示例

public class Recipe
{
  public int RecipeId {get; set;}
  public List<Ingredients> Ingredient {get; set;}
} 

public class Ingredients
{
  public string Name {get; set;}
  public string Amount {get; set;}
}

public ActionResult Index()
{
   Recipe model = new Recipe();
   model.RecipeId = 1;
   model.Ingredient = new List<Ingredients>();//Better if done inside Constructor

   model.Ingredient.Add(new Ingredients{Name = "Salt", 
                                        Amount = "A Pinch"});
   model.Ingredient.Add(new Ingredients{Name = "Hot Sauce", 
                                        Amount = "HOT HOT HOT!"});   
  return View(model);
}

查看

@Html.TextBoxFor(x => x.RecipeId)

  for (int i = 0; i < Model.Ingredient.Count; i++)
    {
          @Html.TextBoxFor(modelItem => Model.Ingredient[i].Name)
          @Html.TextBoxFor(modelItem => Model.Ingredient[i].Amount)
    }

并发布它，它会绑定