C# 我收到MVC5错误（无法在LINQ to Entities查询中构造）

每次我为索引启动网页时，我都会遇到这个错误。我搞不懂这个问题。这可能是一些简单的事情，我正在寻找。如果有人有这样的想法，我们将不胜感激。我不确定错误是来自分页还是搜索功能

这是索引ActionResult上的错误图片

扫描分配控制器

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 ScannerAssignmentList.Models;
using PagedList;

namespace ScannerAssignmentList.Controllers
{
    public class ScannerAssignmentController : Controller
    {
        private ScannerAssignmentDb _db = new ScannerAssignmentDb();

        // GET: ScannerAssignment
        public ActionResult Index(int? page, string searchTerm = null)
        {
            var model =
                   _db.ScannerAssignment
                   .OrderByDescending(r => r.EmployeeName)
                   .Where(r => searchTerm == null || r.EmployeeName.Contains(searchTerm) || r.Model.Contains(searchTerm) || r.Department.Contains(searchTerm) || r.EmployeeNumber.ToString().Contains(searchTerm) || r.Serial.ToString().Contains(searchTerm))
                   .Select(r => new ScannerAssignmentModel

                   {
                       Id = r.Id,
                       EmployeeName = r.EmployeeName,
                       EmployeeNumber = r.EmployeeNumber,
                       Model = r.Model,
                       Serial = r.Serial,
                       Department = r.Department

                   });

            // return View(model);
            return View(model.ToPagedList(page ?? 1, 5));
        }

        // GET: ScannerAssignment/Details/5
        public ActionResult Details(int? id)
        {
            if (id == null)
            {
                return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
            }
            ScannerAssignmentModel scannerAssignmentModel = _db.ScannerAssignment.Find(id);
            if (scannerAssignmentModel == null)
            {
                return HttpNotFound();
            }
            return View(scannerAssignmentModel);
        }

        // GET: ScannerAssignment/Create
        public ActionResult Create()
        {
            return View();
        }

        // POST: ScannerAssignment/Create
        // To protect from overposting attacks, please enable the specific properties you want to bind to, for 
        // more details see http://go.microsoft.com/fwlink/?LinkId=317598.
        [HttpPost]
        [ValidateAntiForgeryToken]
        public ActionResult Create([Bind(Include = "Id,EmployeeName,EmployeeNumber,Model,Serial,Department,Comments")] ScannerAssignmentModel scannerAssignmentModel)
        {
            if (ModelState.IsValid)
            {
                _db.ScannerAssignment.Add(scannerAssignmentModel);
                _db.SaveChanges();
                return RedirectToAction("Index");
            }

            return View(scannerAssignmentModel);
        }

        // GET: ScannerAssignment/Edit/5
        public ActionResult Edit(int? id)
        {
            if (id == null)
            {
                return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
            }
            ScannerAssignmentModel scannerAssignmentModel = _db.ScannerAssignment.Find(id);
            if (scannerAssignmentModel == null)
            {
                return HttpNotFound();
            }
            return View(scannerAssignmentModel);
        }

        // POST: ScannerAssignment/Edit/5
        // To protect from overposting attacks, please enable the specific properties you want to bind to, for 
        // more details see http://go.microsoft.com/fwlink/?LinkId=317598.
        [HttpPost]
        [ValidateAntiForgeryToken]
        public ActionResult Edit([Bind(Include = "Id,EmployeeName,EmployeeNumber,Model,Serial,Department,Comments")] ScannerAssignmentModel scannerAssignmentModel)
        {
            if (ModelState.IsValid)
            {
                _db.Entry(scannerAssignmentModel).State = EntityState.Modified;
                _db.SaveChanges();
                return RedirectToAction("Index");
            }
            return View(scannerAssignmentModel);
        }

        // GET: ScannerAssignment/Delete/5
        public ActionResult Delete(int? id)
        {
            if (id == null)
            {
                return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
            }
            ScannerAssignmentModel scannerAssignmentModel = _db.ScannerAssignment.Find(id);
            if (scannerAssignmentModel == null)
            {
                return HttpNotFound();
            }
            return View(scannerAssignmentModel);
        }

        // POST: ScannerAssignment/Delete/5
        [HttpPost, ActionName("Delete")]
        [ValidateAntiForgeryToken]
        public ActionResult DeleteConfirmed(int id)
        {
            ScannerAssignmentModel scannerAssignmentModel = _db.ScannerAssignment.Find(id);
            _db.ScannerAssignment.Remove(scannerAssignmentModel);
            _db.SaveChanges();
            return RedirectToAction("Index");
        }

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

以下是索引ActionResult的视图

@using PagedList;
@using PagedList.Mvc;

@model IPagedList<ScannerAssignmentList.Models.ScannerAssignmentModel>

@{
    ViewBag.Title = "Index";
}
<br />
<div class="panel panel-primary">
    <div class="panel-heading">
        <h1 class="panel-title">Search Area</h1>
    </div>
    <div class="panel-body">
        <div class="form-group">
            <form method="get">
                @Html.TextBox("searchTerm", null, new { @class = "form-control" })<span class="input-group-btn"></span>
                <div class="panel-footer">
                    <button id="btnSearch"
                            class="btn btn-sm btn-primary">
                        <i class="glyphicon glyphicon-search"></i>
                        &nbsp;Search
                    </button>
                    <a href="@Url.Action("Index", "ScannerAssignment")" class="btn btn-sm btn-primary">
                        <span class="glyphicon glyphicon-cog" aria-hidden="true"></span>
                        Reset
                    </a>
                    <a href="@Url.Action("Create", "ScannerAssignment")" class="btn btn-sm btn-primary">
                        <span class="glyphicon glyphicon-plus-sign" aria-hidden="true"></span>
                        Add

                    </a>
                </div>
            </form>
        </div>
    </div>
</div>

<p>
    @Html.ActionLink("Add New", "Create")
</p>
<table class="table">
    <tr>
        <th>
            @Html.DisplayNameFor(model => model.First().EmployeeName)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.First().EmployeeNumber)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.First().Model)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.First().Serial)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.First().Department)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.First().Comments)
        </th>
        <th></th>
    </tr>

@foreach (var item in Model) {
    <tr>
        <td>
            @Html.DisplayFor(modelItem => item.EmployeeName)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.EmployeeNumber)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.Model)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.Serial)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.Department)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.Comments)
        </td>
        <td>
            @Html.ActionLink("Edit", "Edit", new { id=item.Id }) |
            @Html.ActionLink("Details", "Details", new { id=item.Id }) |
            @Html.ActionLink("Delete", "Delete", new { id=item.Id })
        </td>
    </tr>
}

</table>
@Html.PagedListPager(Model, page => Url.Action("Index", new { page, searchterm = Request.QueryString["searchterm"] }),
new PagedListRenderOptions() { Display = PagedListDisplayMode.IfNeeded, DisplayPageCountAndCurrentLocation = true, DisplayItemSliceAndTotal = true })

ScannerAssignmentDb

using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Linq;
using System.Web;

namespace ScannerAssignmentList.Models
{
    public class ScannerAssignmentDb :DbContext
    {
        public ScannerAssignmentDb()
            : base("name=DefaultConnection")
        {

        }
        public DbSet<ScannerAssignmentModel> ScannerAssignment{ get; set; }
    }
}

使用系统；
使用System.Collections.Generic；
使用System.Data.Entity；
使用System.Linq；
使用System.Web；
名称空间ScannerAssignmentList.Models
{
公共类ScannerAssignmentDb:DbContext
{
公共扫描指定数据库（）
：base（“name=DefaultConnection”）
{
}
公共数据库集扫描分配{get；set；}
}
}

您需要发布

ScannerAssignmentModel

的代码；我怀疑您缺少无参数构造函数，因此LINQ to Entities无法执行新的ScannerAssignmentModel。我添加了模型和数据层。如果您列出（）查询并返回所有结果（不包括分页功能），是否会出现问题？您试图使MVC模型和EF实体具有相同的类？如果是这样的话，

var model=\u db.ScannerAssignment.OrderByDescending（r=>r.EmployeeName）.Where（r=>searchTerm==null | | r.EmployeeName.Contains（searchTerm）.ToList（）

work？该

DbSet

已经

ScannerAssignmentModel

，无需致电

新的ScannerAssignmentModel

进行转换。请稍后回复以获得积分

using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Linq;
using System.Web;

namespace ScannerAssignmentList.Models
{
    public class ScannerAssignmentDb :DbContext
    {
        public ScannerAssignmentDb()
            : base("name=DefaultConnection")
        {

        }
        public DbSet<ScannerAssignmentModel> ScannerAssignment{ get; set; }
    }
}