MVC ASP C# 我的 DeviceID 没有显示在我的视图中

Question

我在尝试让我的 UserID 和 DeviceID（两个独立模型的一部分）显示在我的索引视图之一时遇到了很多麻烦。我正在构建一个网站，允许您通过创建用户（又名患者）添加可以与该用户关联的设备。我通过种子设备列表的下拉列表来做到这一点。虽然下拉列表显示设备，但它不会使用所选设备更新索引。

我的目标是让设备 ID 和名称正确显示在我的用户（又名患者）索引视图上。此外，当我创建和编辑用户时，我希望下拉菜单更新患者（用户）索引视图上的用户信息。

PatientController.cs

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Entity;
using System.Linq;
using System.Net;
using System.Web;
using System.Web.Mvc;
using FaceToFace.Model;
using System.Collections;
using System.ComponentModel.DataAnnotations;

namespace FaceToFaceWebsite.Controllers
{
    public class PatientController : Controller
    {
        private F2FData db = new F2FData();

        //
        // GET: /Patient/

        public ActionResult Index()
        {

            return View(db.Users.ToList());
        }

        //
        // GET: /Patient/Details/5

        public ActionResult Details(int? id)
        {
            if (id == null)
            {
                return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
            }
            User user = db.Users.Find(id);
            if (user == null)
            {
                return HttpNotFound();
            }
            return View(user);
        }


        // GET: /Patient/Create

        public ActionResult Create()
        {

            ViewBag.DeviceID = new SelectList(db.Devices, "DeviceID", "Name");
            return View();
        }

        //
        // POST: /Patient/Create

        [HttpPost]
        [ValidateAntiForgeryToken]
        public ActionResult Create([Bind(Include = "UserID,CodeName,UseBriefInstructions")] User user, Device device)
        {
            if (ModelState.IsValid)
            {
                //db.Devices = user.Device.DeviceID;
                db.Users.Add(user);
                db.SaveChanges();
                return RedirectToAction("Index");
            }

            ViewBag.DeviceID = new SelectList(db.Devices, "DeviceID", "Name", user.Device.DeviceID);
            return View(user);
        }

        //
        // GET: /Patient/Edit/5

        public ActionResult Edit(int? id)
        {
            if (id == null)
            {
                return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
            }
            User user = db.Users.Find(id);
            if (user == null)
            {
                return HttpNotFound();
            }
            //removed   user.Device.DeviceID
            ViewBag.DeviceID = new SelectList(db.Devices, "DeviceID", "Name");
            return View(user);
        }

        //
        // POST: /Patient/Edit/5

        [HttpPost]
        [ValidateAntiForgeryToken]
        public ActionResult Edit([Bind(Include = "UserID,CodeName,UseBriefInstructions")] User user)
        {
            if (ModelState.IsValid)
            {
                db.Entry(user).State = EntityState.Modified;
                db.SaveChanges();
                return RedirectToAction("Index");
            }

            ViewBag.DeviceID = new SelectList(db.Devices, "DeviceID", "Name", user.Device.DeviceID);
            return View(user);
        }

        //
        // GET: /Patient/Delete/5

        public ActionResult Delete(int? id)
        {
            if (id == null)
            {
                return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
            }
            User user = db.Users.Find(id);
            if (user == null)
            {
                return HttpNotFound();
            }
            return View(user);

        }

        //
        // POST: /Patient/Delete/5

        [HttpPost, ActionName("Delete")]
        [ValidateAntiForgeryToken]
        public ActionResult DeleteConfirmed(int id)
        {
            User user = db.Users.Find(id);
            db.Users.Remove(user);
            db.SaveChanges();
            return RedirectToAction("Index");
        }

        protected override void Dispose(bool disposing)
        {
            db.Dispose();
            base.Dispose(disposing);
        }
    }
}

User.cs（型号）

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace FaceToFace.Model
{
    public class User
    {

        public int UserID { get; set; }

        public string CodeName { get; set; }

        public bool UseBriefInstructions { get; set; }

        public Device Device { get; set; }
    }
}

Device.cs（型号）

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace FaceToFace.Model
{
    public class Device
    {
        public int DeviceID { get; set; }
        public string Name { get; set; }
    }
}

Views/Patient/Index.cshtml

@model IEnumerable<FaceToFace.Model.User>

@{
    ViewBag.Title = "Index";
}

<h2>Your Patients</h2>

Showing @Model.Count() users

<p>
    @Html.ActionLink("Add New User", "Create")
</p>

<table>
    <tr>
        <th>
            @Html.DisplayNameFor(model => model.UserID)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.CodeName)
        </th>
        <th>
            @*@Html.DisplayNameFor(model => model.Device.Name)*@Device
        </th>
        <th>
            @Html.DisplayNameFor(model => model.Device.DeviceID)
        </th>

    </tr>

    @foreach (var item in Model)
    {
        <tr>
            <td>
                @Html.DisplayFor(modelItem => item.UserID)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.CodeName)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.Device.Name)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.Device.DeviceID)
            </td>
            <td>
                @Html.ActionLink("Edit", "Edit", new { id = item.UserID }) |
                @Html.ActionLink("Details", "Details", new { id = item.UserID }) |
                @Html.ActionLink("Delete", "Delete", new { id = item.UserID })
            </td>
        </tr>
    }

</table>

Views/Patient/Create.cshtml

    @model FaceToFace.Model.User

    @{
        ViewBag.Title = "Create";
    }

    <h2>Create</h2>

    @using (Html.BeginForm()) {
        @Html.AntiForgeryToken()
        @Html.ValidationSummary(true)

        <fieldset>
            <legend>User</legend>

            <div class="editor-label">
                @Html.LabelFor(model => model.CodeName)
            </div>
            <div class="editor-field">
                @Html.EditorFor(model => model.CodeName)
                @Html.ValidationMessageFor(model => model.CodeName)
            </div>

            <div class="editor-label">
                @Html.LabelFor(model => model.Device.Name, "Device")
            </div>
            <div class="editor-field">
                @Html.DropDownList("DeviceID", String.Empty)
            </div>

            <div class="editor-label">
                @Html.LabelFor(model => model.UseBriefInstructions)
            </div>
            <div class="editor-field">
                @Html.EditorFor(model => model.UseBriefInstructions)
                @Html.ValidationMessageFor(model => model.UseBriefInstructions)
            </div>

            <p>
                <input type="submit" value="Create" />
            </p>
        </fieldset>
    }

<div>
    @Html.ActionLink("Back to List", "Index")
</div>

Views/Patient/Edit.cshtml

@model FaceToFace.Model.User

@{
    ViewBag.Title = "Edit";
}

<h2>Edit</h2>

@using (Html.BeginForm()) {
    @Html.AntiForgeryToken()
    @Html.ValidationSummary(true)

    <fieldset>
        <legend>User</legend>

        @Html.HiddenFor(model => model.UserID)

        <div class="editor-label">
            @Html.LabelFor(model => model.CodeName)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.CodeName)
            @Html.ValidationMessageFor(model => model.CodeName)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.Device.Name, "Device")
        </div>
        <div class="editor-field">
            @Html.DropDownList("DeviceID", String.Empty)

        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.UseBriefInstructions)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.UseBriefInstructions)
            @Html.ValidationMessageFor(model => model.UseBriefInstructions)
        </div>

        <p>
            <input type="submit" value="Save" />
        </p>
    </fieldset>
}

<div>
    @Html.ActionLink("Back to List", "Index")
</div>

感谢您花时间阅读本文，我是 MVC 的新手，所以非常感谢您提供的任何帮助。

更新

在 Jason 的帮助下，我开始构建视图模型。我在我的视图模型中使用的模型在我加入我的解决方案的另一个项目中。

UserDeviceViewModel.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.WebPages.Html;
using FaceToFace.Model;

namespace FaceToFaceWebsite.Models
{
    public class UserDeviceViewModel
    {
        public UserDeviceViewModel()
        {
            User = new User();
            Users = new List<User>();
            Devices = new List<SelectListItem>();
        }

        public User UseBriefInstructions { get; set; }
        public Device Device { get; set; }
        public User User { get; set; }
        public User CodeName { get; set; }
        public IList<SelectListItem> Devices { get; set; }
        public IList<User> Users { get; set; }
    }
}

PatientController.cs

namespace FaceToFaceWebsite.Controllers
{
    public class PatientController : Controller
    {
        private F2FData db = new F2FData();

        //
        // GET: /Patient/
        [HttpPost]
        [ValidateAntiForgeryToken]
        public ActionResult Index(UserDeviceViewModel viewModelDevice)
        {

            var viewModel = new UserDeviceViewModel();

            viewModel.Devices.Add(new SelectListItem() { Text = "MAU110-10", Value = "1" });
            viewModel.Devices.Add(new SelectListItem() { Text = "MAU110-100", Value = "2" });
            viewModel.Devices.Add(new SelectListItem() { Text = "MAU110-101", Value = "3" });
            viewModel.Devices.Add(new SelectListItem() { Text = "MAU110-102", Value = "4" });
            viewModel.Devices.Add(new SelectListItem() { Text = "MAU110-103", Value = "5" });

            viewModel.Users.AddRange(db.Users.ToList());

            return View(viewModel);
        }

Views/Patient/Create.cshtml

    @model FaceToFace.Model.User

    @{
        ViewBag.Title = "Create";
    }

    <h2>Create</h2>

    @using (Html.BeginForm()) {
        @Html.AntiForgeryToken()
        @Html.ValidationSummary(true)

        <fieldset>
            <legend>User</legend>

            <div class="editor-label">
                @Html.LabelFor(model => model.CodeName)
            </div>
            <div class="editor-field">
                @Html.EditorFor(model => model.CodeName)
                @Html.ValidationMessageFor(model => model.CodeName)
            </div>

            <div class="editor-label">
                @Html.LabelFor(model => model.Device.Name, "Device")
            </div>
            <div class="editor-field">
                @Html.DropDownListFor(model => model.User.Device.DeviceID, Model.Devices)
        <input type="submit" value="Save" />
            </div>

            <div class="editor-label">
                @Html.LabelFor(model => model.UseBriefInstructions)
            </div>
            <div class="editor-field">
                @Html.EditorFor(model => model.UseBriefInstructions)
                @Html.ValidationMessageFor(model => model.UseBriefInstructions)
            </div>

            <p>
                <input type="submit" value="Create" />
            </p>
        </fieldset>
    }

<div>
    @Html.ActionLink("Back to List", "Index")
</div>

我将省略编辑以避免更多的垃圾邮件，但是我现在收到多个错误。我已经修复了一些我相信。对于下拉菜单，我收到此错误：

'System.Web.Mvc.HtmlHelper' 不包含 'DropDownListFor' 的定义并且最佳扩展方法重载 'System.Web.Mvc.Html.SelectExtensions.DropDownListFor(System.Web.Mvc.HtmlHelper, System.Linq.Expressions.Expression>, System.Collections.Generic.IEnumerable)' 有一些无效参数

对于患者控制器中的 viewModel.Devices.Add，我得到：

'System.Collections.Generic.ICollection.Add(System.Web.WebPages.Html.SelectListItem)' 的最佳重载方法匹配有一些无效参数

连同：

参数 1：无法从 'System.Web.Mvc.SelectListItem' 转换为 'System.Web.WebPages.Html.SelectListItem'

最后在下方我收到来自 AddRange 的错误消息：

'System.Collections.Generic.IList' 不包含 'AddRange' 的定义，并且找不到接受类型 'System.Collections.Generic.IList' 的第一个参数的扩展方法 'AddRange'（您是否缺少 using 指令或程序集引用？）

如果您能帮助我们完成这项工作，我们将不胜感激。再次抱歉垃圾邮件！

Answer 1

您似乎没有提供可供选择的设备的视图。

不过，总的来说，我建议您在这里使用视图模型方法。例如

用户

public class User
{
    public User()
    {
        Device = new Device();
    }

    public int UserID { get; set; }

    public string CodeName { get; set; }

    public bool UseBriefInstructions { get; set; }

    public Device Device { get; set; }
}

设备

public class Device
{
    public int DeviceID { get; set; }

    public string Name { get; set; }
}

然后有一个viewmodel class:

public class CreatePatientViewModel
{
    public CreatePatientViewModel()
    {
        User = new User();
        Devices = new List<SelectListItem>();
    }

    public User User { get; set; }

    public IList<SelectListItem> Devices { get; set; }
}

在控制器中，您可以像这样使用视图模式 -

public ActionResult Index()
{
    var viewModel = new CreatePatientViewModel();

    viewModel.Devices.Add(new SelectListItem() { Text = "Device 1", Value = "1" });
    viewModel.Devices.Add(new SelectListItem() { Text = "Device 2", Value = "2" });

    return View(viewModel);
}

然后 .Devices 属性可用于填充视图中的下拉列表，例如

@model WhosebugMvc.Controllers.CreatePatientViewModel

@using (Html.BeginForm())
{
    @Html.DropDownListFor(model => model.User.Device.DeviceID, Model.Devices)
    <input type="submit" value="Save" />
}

以及提交数据时：

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Index(CreatePatientViewModel viewModel)
{
    // Do whatever you want with the data.
    // viewModel.User.Device.DeviceId will be given the value selected from the dropdown.
    return View(viewModel);
}

不要理会 [Bind(Include = "UserID,Code.... 的东西，它只会让事情变得混乱。 CreatePatientViewModel 可用于从提交的表单中获取值，例如

@Html.InputFor(model => model.User.Code)

在视图中，如果上面的文本框输入了值，那么当创建 POST 时，CreatePatientViewModel.User.Code 将传递该值，因为它与使用的 model.User.Code 匹配.

希望以上内容对您有所帮助。

编辑：

在您的控制器的 Index 操作方法中，您可以执行如下操作：

public ActionResult Index()
{
    var viewModel = new CreatePatientViewModel();

    viewModel.Devices.Add(new SelectListItem() { Text = "Device 1", Value = "1" });
    viewModel.Devices.Add(new SelectListItem() { Text = "Device 2", Value = "2" });

    viewModel.Users.AddRange(db.Users.ToList());

    return View(viewModel);
}

更改 CreatePatientViewModel 以包含 Users 属性:

public class CreatePatientViewModel
{
    public CreatePatientViewModel()
    {
        User = new User();
        Users = new List<User>();
        Devices = new List<SelectListItem>();
    }

    public User User { get; set; }

    public IList<SelectListItem> Devices { get; set; }

    public IList<User> Users { get; set; }
}

请注意，我假设您的 db.Users 列表是 User 对象的列表，如果不是，则只需将其更改为它应该是的任何类型。

MVC ASP C# 我的 DeviceID 没有显示在我的视图中

MVC ASP C# My DeviceID is not displaying on my views

c#

linq

asp.net-mvc

razor

asp.net-mvc-4