[英]EntityFramework many to many realation in project MVC
我有三個表TaskModels,TaskAssigned和Users(AspNetUsers)。 我使用Task TaskModels創建新任務,使用Task Assigned模型創建此任務給用戶。 一切正常,但是當我在圖像中發布時,我只是獲得了分配給用戶的用戶ID和任務ID女巫。 但我想查看用戶名任務名稱而不是其ID。 這是我的代碼和結果img。
public class TaskAssigned
{
public int Id { get; set; }
public int TaskModelId { get; set; }
public int UserId { get; set; }
public TasksModel TasksModel { get; set; }
public ApplicationUser User { get; set; }
}
public class TasksModel
{
public int Id { get; set; }
[Required(ErrorMessage = "Heading is required")]
public string Heading { get; set; }
[Required(ErrorMessage = "Content is required")]
public string Content { get; set; }
[Required(ErrorMessage = "Start Date is required")]
[DisplayName(displayName: "Start Date")]
public DateTime StartDate { get; set; }
[Required(ErrorMessage = "Deadline is required")]
[DisplayName(displayName: "Deadline")]
public int DeadlineTask { get; set; }
}
public class ApplicationUser
{
public string Name { get; set; }
public List<TaskAssigned> TaskAssigneds { get; set; }
}
這是我的TaskAssignedsController
public class TaskAssignedsController : Controller
{
private ApplicationDbContext db = new ApplicationDbContext();
// GET: TaskAssigneds
public ActionResult Index()
{
var list = db.TaskAssigneds.Include(o => o.TasksModel).Include(o => o.User);
return View(list.ToList());
}
// GET: TaskAssigneds/Create
public ActionResult Create()
{
ViewBag.TaskModelId = new SelectList(db.TasksModels,"Id", "Heading");
ViewBag.UserId = new SelectList(db.Users, "ApplicationUserId", "UserName");
return View();
}
// POST: TaskAssigneds/Create
// To protect from overposting attacks, please enable the specific properties you want to bind to, for
// more details see https://go.microsoft.com/fwlink/?LinkId=317598.
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Create([Bind(Include = "Id,TaskModelId,UserId")] TaskAssigned taskAssigned)
{
if (ModelState.IsValid)
{
db.TaskAssigneds.Add(taskAssigned);
db.SaveChanges();
return RedirectToAction("Index");
}
ViewBag.TaskModelId = new SelectList(db.TasksModels, "Id", "Heading", taskAssigned.TasksModel.Heading);
ViewBag.UserId = new SelectList(db.Users, "ApplicationUserId", "UserName", taskAssigned.User.UserName);
return View(taskAssigned);
}
解決該問題的更簡單方法(不推薦)是:
@Html.DisplayFor(modelItem => item.TaskModelId)
@Html.DisplayFor(modelItem => item.UserId)
用這個:
@Html.DisplayFor(modelItem => item.TasksModel.Name)
@Html.DisplayFor(modelItem => item.User.Name)
但是,看起來您的TasksModel
沒有名稱屬性。 另外,您還應該修復@Html.DisplayNameFor
(對於兩列)。
現在,我建議創建一個像這樣的視圖模型 :
public class TasksAssignedViewModel
{
public int TaskModelId { get; set; }
public int UserId { get; set; }
public int TaskModelName { get; set; }
public int UserName { get; set; }
}
..然后在“索引”操作中,將查詢投影到該視圖模型中,如下所示:
public ActionResult Index()
{
var list = db.TaskAssigneds.Select(l => new TasksAssignedViewModel
{
TaskModelId = l.TasksModel.Id,
UserId = l.User.Id,
TaskModelName = l.TasksModel.Name,
UserName = l.User.Name
});
return View(list.ToList());
}
...最終在您的Index.cshtml
,編輯模型的類型:
@model IEnumerable<DeadLiner.Models.TasksAssignedViewModel>
這樣,就不再需要使用Include
。 由於您不再從數據庫中獲取所有字段,因此這也使查詢速度更快。
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