C# 我的ViewModel导致多个错误_C#_Asp.net_Asp.net Mvc_Entity Framework_Asp.net Mvc 4

C# 我的ViewModel导致多个错误

c# asp.net asp.net-mvc entity-framework asp.net-mvc-4

C# 我的ViewModel导致多个错误,c#,asp.net,asp.net-mvc,entity-framework,asp.net-mvc-4,C#,Asp.net,Asp.net Mvc,Entity Framework,Asp.net Mvc 4,我正在尝试创建一个viewmodel，这样我就可以在一个页面上显示从多个模型收集的信息，但是我遇到了多个错误（如下所示），因为所使用的模型是我解决方案中不同项目的一部分。任何帮助都将不胜感激。在显示信息的同时，我尝试创建一个下拉列表，当用户被创建时，他们可以选择每个用户正在使用的设备 User.cs（型号） UserDeviceViewModel.cs using System; using System.Collections.Generic; using System.Linq; using

我正在尝试创建一个viewmodel，这样我就可以在一个页面上显示从多个模型收集的信息，但是我遇到了多个错误（如下所示），因为所使用的模型是我解决方案中不同项目的一部分。任何帮助都将不胜感激。在显示信息的同时，我尝试创建一个下拉列表，当用户被创建时，他们可以选择每个用户正在使用的设备

User.cs（型号）

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; }
    }
}

 using System;
using System.Collections;
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.ComponentModel.DataAnnotations;
using FaceToFaceWebsite.Models;

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);
        }

        // 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);
        }

        public ActionResult Create()
        {
            // was ViewBag.DeviceID = new SelectList(db.Devices, "DeviceID", "Name");
            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);
            //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);
        }
    }
}

public ActionResult Index(UserDeviceViewModel viewModelDevice)
        {
            var viewModel = new UserDeviceViewModel(); 

            List<UserDeviceViewModel> viewModelList = new List<UserDeviceViewModel>();
            viewModelDevice.Users.AddRange(db.Users.ToList());
            return View(viewModelList);
        }

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

        public Device Device { get; set; }
        public Device Name { get; set; }
        public Device DeviceID { get; set; }

        public User UseBriefInstructions { get; set; }
        public User User { get; set; }
        public User UserID { get; set; }
        public User CodeName { get; set; }

        public List<SelectListItem> Devices { get; set; }
        public List<User> Users { get; set; }
    }
}

我将省略编辑视图，以避免进一步的垃圾邮件，它基本上包含类似的功能创建，但我现在得到多个错误。我相信我已经解决了一些问题。对于下拉列表（创建），我得到以下错误：

“System.Web.Mvc.HtmlHelper”不包含“DropDownListFor”的定义，而“System.Web.Mvc.Html.SelectExtensions.DropDownListFor（System.Web.Mvc.HtmlHelper，System.Linq.Expressions.Expression>，System.Collections.Generic.IEnumerable）”的最佳扩展方法重载包含一些无效参数

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; }
    }
}

 using System;
using System.Collections;
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.ComponentModel.DataAnnotations;
using FaceToFaceWebsite.Models;

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);
        }

        // 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);
        }

        public ActionResult Create()
        {
            // was ViewBag.DeviceID = new SelectList(db.Devices, "DeviceID", "Name");
            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);
            //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);
        }
    }
}

public ActionResult Index(UserDeviceViewModel viewModelDevice)
        {
            var viewModel = new UserDeviceViewModel(); 

            List<UserDeviceViewModel> viewModelList = new List<UserDeviceViewModel>();
            viewModelDevice.Users.AddRange(db.Users.ToList());
            return View(viewModelList);
        }

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

        public Device Device { get; set; }
        public Device Name { get; set; }
        public Device DeviceID { get; set; }

        public User UseBriefInstructions { get; set; }
        public User User { get; set; }
        public User UserID { get; set; }
        public User CodeName { get; set; }

        public List<SelectListItem> Devices { get; set; }
        public List<User> Users { get; set; }
    }
}

对于我获得的

viewModel.Devices.Add

患者控制器：

与“System.Collections.Generic.ICollection.Add（System.Web.WebPages.Html.SelectListItem）”匹配的最佳重载方法有一些无效参数

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; }
    }
}

 using System;
using System.Collections;
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.ComponentModel.DataAnnotations;
using FaceToFaceWebsite.Models;

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);
        }

        // 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);
        }

        public ActionResult Create()
        {
            // was ViewBag.DeviceID = new SelectList(db.Devices, "DeviceID", "Name");
            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);
            //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);
        }
    }
}

public ActionResult Index(UserDeviceViewModel viewModelDevice)
        {
            var viewModel = new UserDeviceViewModel(); 

            List<UserDeviceViewModel> viewModelList = new List<UserDeviceViewModel>();
            viewModelDevice.Users.AddRange(db.Users.ToList());
            return View(viewModelList);
        }

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

        public Device Device { get; set; }
        public Device Name { get; set; }
        public Device DeviceID { get; set; }

        public User UseBriefInstructions { get; set; }
        public User User { get; set; }
        public User UserID { get; set; }
        public User CodeName { get; set; }

        public List<SelectListItem> Devices { get; set; }
        public List<User> Users { get; set; }
    }
}

以及：

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

最后，下面是我从AddRange（PatientController）收到的一个错误：

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

***更新***

更改为PatientController.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; }
    }
}

 using System;
using System.Collections;
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.ComponentModel.DataAnnotations;
using FaceToFaceWebsite.Models;

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);
        }

        // 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);
        }

        public ActionResult Create()
        {
            // was ViewBag.DeviceID = new SelectList(db.Devices, "DeviceID", "Name");
            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);
            //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);
        }
    }
}

public ActionResult Index(UserDeviceViewModel viewModelDevice)
        {
            var viewModel = new UserDeviceViewModel(); 

            List<UserDeviceViewModel> viewModelList = new List<UserDeviceViewModel>();
            viewModelDevice.Users.AddRange(db.Users.ToList());
            return View(viewModelList);
        }

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

        public Device Device { get; set; }
        public Device Name { get; set; }
        public Device DeviceID { get; set; }

        public User UseBriefInstructions { get; set; }
        public User User { get; set; }
        public User UserID { get; set; }
        public User CodeName { get; set; }

        public List<SelectListItem> Devices { get; set; }
        public List<User> Users { get; set; }
    }
}

公共操作结果索引（UserDeviceViewModel viewModelDevice） { var viewModel=new UserDeviceViewModel（）； List viewModelList=新列表（）； viewModelDevice.Users.AddRange（db.Users.ToList（））；返回视图（viewModelList）； } 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; }
    }
}

 using System;
using System.Collections;
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.ComponentModel.DataAnnotations;
using FaceToFaceWebsite.Models;

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);
        }

        // 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);
        }

        public ActionResult Create()
        {
            // was ViewBag.DeviceID = new SelectList(db.Devices, "DeviceID", "Name");
            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);
            //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);
        }
    }
}

public ActionResult Index(UserDeviceViewModel viewModelDevice)
        {
            var viewModel = new UserDeviceViewModel(); 

            List<UserDeviceViewModel> viewModelList = new List<UserDeviceViewModel>();
            viewModelDevice.Users.AddRange(db.Users.ToList());
            return View(viewModelList);
        }

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

        public Device Device { get; set; }
        public Device Name { get; set; }
        public Device DeviceID { get; set; }

        public User UseBriefInstructions { get; set; }
        public User User { get; set; }
        public User UserID { get; set; }
        public User CodeName { get; set; }

        public List<SelectListItem> Devices { get; set; }
        public List<User> Users { get; set; }
    }
}

命名空间FaceWebSite.Models { 公共类UserDeviceViewModel { 公共用户设备视图模型（） { 设备=新设备（）； User=新用户（）；用户=新列表（）；设备=新列表（）； } 公用设备设备{get；set；} 公用设备名称{get；set；} 公用设备设备ID{get；set；} 公共用户使用说明{get；set；} 公共用户{get；set；} 公共用户用户ID{get；set；} 公共用户代码名{get；set；} 公共列表设备{get；set；} 公共列表用户{get；set；} } } Index.cshtml（查看）

@model IEnumerable
@*@模型IEnumerable*@
@{
ViewBag.Title=“Index”；
}
你的病人
@*显示@Model.Count（）用户*@

@ActionLink（“添加新用户”、“创建”）

@DisplayNameFor（model=>model.UserID）
@DisplayNameFor（model=>model.CodeName）
@*@Html.DisplayNameFor（model=>model.Device.Name）*@Device
@DisplayNameFor（model=>model.Device.DeviceID）
@foreach（模型中的var项目）
{
@DisplayFor（modelItem=>item.UserID）
@DisplayFor（modelItem=>item.CodeName）
@DisplayFor（modelItem=>item.Device.Name）
@DisplayFor（modelItem=>item.Device.DeviceID）
@ActionLink（“编辑”，“编辑”，新的{id=item.UserID}）|
@ActionLink（“详细信息”，“详细信息”，新的{id=item.UserID}）|
@ActionLink（“删除”，“删除”，新的{id=item.UserID}）
}

我已经让它运行没有错误，但是我最初的问题是没有来自数据库的数据显示在索引视图上。当我创建新用户时，它也不会显示。

对于DropDownList（您已经声明了用户模型）：

@model FaceToFace.model.User
....
@Html.DropDownListFor（model=>model.Device.DeviceID，（IEnumerable）ViewBag.DeviceID）

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

对于上述错误，

DeviceID

是一个int，它需要是一个字符串，

Devices

需要是一个

IEnumerable

：

@Html.DropDownListFor(model => model.User.Device.DeviceID, Model.Devices)

因此，将public

IList设备{get；set；}

更改为

public IEnumerable设备{get；set；}

匹配的最佳重载方法 'System.Collections.Generic.ICollection.Add（System.Web.WebPages.Html.SelectListItem）' 有一些无效的参数与“System.Collections.Generic.ICollection.Add（System.Web.WebPages.Html.SelectListItem）”匹配的最佳重载方法有一些无效的参数

上述两个错误引用之间存在某种不匹配，您的控制器使用System.Web.Mvc使用

该视图正在以某种方式拾取System.Web.WebPages.Html
，请检查是否存在