在mvc中的下拉列表中使用外键

Question

我是MVC的新手,并坚持应该是一个非常直接的问题.我正在完成这个教程并得到了一切非常有用的工作,除了我现在想要添加一个外键'链接'(不确定它叫什么)但似乎无法让它工作.这就是我所拥有的:

表:

 Inventory:
 Id   |  SerialNumber  | ManufacturerId (foreignkey to Manufactueres->id)

 Manufactureres
 Id (primary key)   |  Name

模型(InventoryItem.cs):

 public class InventoryItem {
     public int Id {get; set; }
     public int SerialNumber{ get; set; }

     //this starts the trouble, I actually want to interact with the Manufactureres table -> Name column
     public int ManufacturerId { get; set; }  
 }

查看(Create.cshtml):

 ...
 //What i really want is a dropdown of the values in the Manufactureres table
 @Html.EditorFor(model=> model.ManufacturerId)

当使用关系数据库时,这必然是一个常见的问题,将会有许多外键关系被使用/显示,但由于某种原因,我无法在stackoverflow上找到直接对应于如此简单的东西的教程或问题.非常感谢任何指导或方向!谢谢,

Answer 1

我希望我能正确理解你的问题.似乎您想要添加新的库存项目,然后您需要下拉列表中的所有制造商的列表.我打算做这个假设,如果我不在赛道上,请告诉我:)

首先去创建一个视图模型.此视图模型将绑定到yout视图.永远不要将域对象绑定到您的视图.

public class InventoryItemViewModel
{
     public int SerialNumber { get; set; }

     public int ManufacturerId { get; set; }

     public IEnumerable<Manufacturer> Manufacturers { get; set; }
}

您的域对象:

public class InventoryItem
{
     public int Id { get; set; }

     public int SerialNumber{ get; set; }

     public int ManufacturerId { get; set; }
}

public class Manufacturer
{
     public int Id { get; set; }

     public string Name { get; set; }
}

您的控制器可能如下所示:

public class InventoryItemController : Controller
{
     private readonly IManufacturerRepository manufacturerRepository;
     private readonly IInventoryItemRepository inventoryItemRepository;

     public InventoryItem(IManufacturerRepository manufacturerRepository, IManufacturerRepository manufacturerRepository)
     {
          // Check that manufacturerRepository and inventoryItem are not null

          this.manufacturerRepository = manufacturerRepository;
          this.inventoryItemRepository = inventoryItemRepository;
     }

     public ActionResult Create()
     {
          InventoryItemViewModel viewModel = new InventoryItemViewModel
          {
               Manufacturers = manufacturerRepository.GetAll()
          };

          return View(viewModel);
     }

     [HttpPost]
     public ActionResult Create(InventoryItemViewModel viewModel)
     {
          // Check that viewModel is not null

          if (!ModelState.IsValid)
          {
               Manufacturers = manufacturerRepository.GetAll()

               return View(viewModel);
          }

          // All validation is cool

          // Use a mapping tool like AutoMapper
          // to map between view model and domain model
          InventoryItem inventoryItem = Mapper.Map<InventoryItem>(viewModel);

          inventoryItemRepository.Insert(inventoryItem);

          // Return to which ever view you need to display
          return View("List");
     }
}

然后在您的视图中,您可能会有以下内容:

@model MyProject.DomainModel.ViewModels.InventoryItems.InventoryItemViewModel

<table>
     <tr>
          <td class="edit-label">Serial Number <span class="required">**</span></td>
          <td>@Html.TextBoxFor(x => x.SerialNumber, new { maxlength = "10" })
              @Html.ValidationMessageFor(x => x.SerialNumber)
          </td>
     </tr>
     <tr>
          <td class="edit-label">Manufacturer <span class="required">**</span></td>
          <td>
               @Html.DropDownListFor(
                    x => x.ManufacturerId,
                    new SelectList(Model.Manufacturers, "Id", "Name", Model.ManufacturerId),
                    "-- Select --"
               )
               @Html.ValidationMessageFor(x => x.ManufacturerId)
          </td>
     </tr>
</table>

我希望这有帮助 :)