如何制作一个创建控制器及其 ViewModel

Question

在 Create 视图中，管理员可以创建一个新菜并从下拉列表中选择其类型（DishTypes 来自数据库）。问题是我不知道如何在Create 视图中设计DishesViewModel、DishesController 和下拉列表。

这是Dishes模型

public class Dishes
{ 
  [Key]
  [Required]
  public int DishID { get; set; }

  [Required]
  public string Dishname { get; set; }

  public int DishTypeID { get; set; }

  [ForeignKey("DishTypeID")]
  public virtual DishTypes DishTypes { get; set; }
}

这里是 DishTypes 模型

public class DishTypes
{
    [Required]
    public int DishTypeID { get; set; }

    [Required]
    public string DishTypeName { get; set; }
}

这是我目前的 Dishes 视图模型（我使用 Automapoper 将它们映射到域模型）

public class DishesVM
{

   [Required]
   public string DishName{ get; set; }

   [Required]
   public int DishTypeID{ get; set; }

   [Required]
   public string DishTypeName { get; set; }

}

这是 DishesController

public class DishesController: Controller  
{

   [HttpGet]
   public async Task<IActionResult> Create()
   {
      // it should  pass a list of dishTypes to my view so when admins create a dish they can choose dishtype from a dropdown list

     //I down't want to use ViewBag or ViewData
      return View()
   }
}

这是创建视图

@model  DataLayers.Models.ViewModels.DishesVM

<form  asp-controller="Dishes" asp-action="Create">
    <label class="label" asp-for="Dishname"></label>
    <input class="input" type="text" asp-for="Dishname">

    //a drop down list, which enables admins choose dishtypes, is needed here
</form

最后是 DishRepository

public class DishRepository
{
   public async Task<IEnumerable<Dishes>> GetAllDishesAsync()
     {
         return await _RepositoryContext.Set<Dishes>().ToListAsync();
     }
}

随意改变一切。

Answer 1

尝试以下步骤：

1. 更改视图模型

   public class DishesVM
   {
   
       [Required]
       public string DishName { get; set; }
   
       [Required]
       public int DishTypeID { get; set; }
   
       public List<DishTypes> DishTypes { get; set; }
   }
   

2. 查看

   <div class="row">
       <div class="col-md-4">
           <form asp-action="Create">
               <div asp-validation-summary="ModelOnly" class="text-danger"></div>
               <div class="form-group">
                   <label asp-for="DishName" class="control-label"></label>
                   <input asp-for="DishName" class="form-control" />
                   <span asp-validation-for="DishName" class="text-danger"></span>
               </div>
               <div class="form-group">
                   <label asp-for="DishTypeID" class="control-label"></label>
                   <select asp-for="DishTypeID"
                           class="dropdown"
                           asp-items="@(new SelectList(Model.DishTypes, "DishTypeID" ,"DishTypeName"))"></select>
                   <span asp-validation-for="DishTypeID" class="text-danger"></span>
               </div>
               <div class="form-group">
                   <input type="submit" value="Create" class="btn btn-primary" />
               </div>
           </form>
       </div>
   </div>
   

3. 控制器

   [HttpGet]
   public async Task<IActionResult> Create()
   {
       var types = await _context.DishTypes.ToListAsync();
       var vm = new DishesVM {
           DishTypes = types
       };
       return View(vm);
   }
   [HttpPost]
   public async Task<IActionResult> Create(DishesVM vm)
   {
       return Ok(vm);
   }