我已经学习MVC 5几周了，一直没有遇到什么问题，直到昨天。昨晚我打开VS来处理我的项目时，一切都正常工作。但是现在出现了以下问题：
首先，我停止了当前的项目，创建了一个使用相同数据库模型的新项目。该数据库是Azure SQL数据库。对于我创建的每个对象，我都创建了自己的类来应用数据注释，就像这样：（由于有很多数据注释，我删除了它们，但错误仍然存在）。
首先，我停止了当前的项目，创建了一个使用相同数据库模型的新项目。该数据库是Azure SQL数据库。对于我创建的每个对象，我都创建了自己的类来应用数据注释，就像这样：（由于有很多数据注释，我删除了它们，但错误仍然存在）。
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Text;
namespace Dyad.GreenvilleFoodTrucks.Data
{
[MetadataType(typeof(LocationMetadata))]
public partial class Location
{
}
public class LocationMetadata
{
public int ID { get; set; }
public int TruckID { get; set; }
public Nullable<System.DateTime> StartTime { get; set; }
public Nullable<System.DateTime> EndTime { get; set; }
public Nullable<System.DateTime> Date { get; set; }
public string Description { get; set; }
public string Address { get; set; }
public string State { get; set; }
public string ZIP { get; set; }
public virtual Truck Truck { get; set; }
}
}
并且，这是从我的数据库创建的对象EF：
namespace Dyad.GreenvilleFoodTrucks.Data
{
using System;
using System.Collections.Generic;
public partial class Location
{
public int ID { get; set; }
public int TruckID { get; set; }
public Nullable<System.DateTime> StartTime { get; set; }
public Nullable<System.DateTime> EndTime { get; set; }
public Nullable<System.DateTime> Date { get; set; }
public string Description { get; set; }
public string Address { get; set; }
public string State { get; set; }
public string ZIP { get; set; }
public virtual Truck Truck { get; set; }
}
}
我使用新创建的模型创建了一个支架项目，使用的上下文是 EF 创建的上下文而不是 ApplicationDBContext。
现在当我进入生成的视图时，ViewBag.Title = "title" 会给我这个错误："需要编译动态表达式的一个或多个类型无法找到。您是否缺少引用？" 请注意，这在所有 CRUD cshtml 文件以及索引文件中都会发生。
此外，每个 @Html.LabelFor / @Html.DisplayNameFor 以及以 "For" 结尾的任何内容都会给我这个错误："无法从使用中推断方法 'System.Web.Mvc.Html.DisplayNameExtensions.DisplayNameFor(System.Web.Mvc.HtmlHelper, System.Linq.Expressions.Expression>)' 的类型参数。请明确指定类型参数。"
以下是视图的示例。这是全部自动生成的，所以我没有更改任何内容。
@model Dyad.GreenvilleFoodTrucks.Data.Location
@{
ViewBag.Title = "Create";
}
<h2>Create</h2>
@using (Html.BeginForm())
{
@Html.AntiForgeryToken()
<div class="form-horizontal">
<h4>Location</h4>
<hr />
@Html.ValidationSummary(true, "", new { @class = "text-danger" })
<div class="form-group">
@Html.LabelFor(model => model.TruckID, "TruckID", htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.DropDownList("TruckID", null, htmlAttributes: new { @class = "form-control" })
@Html.ValidationMessageFor(model => model.TruckID, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.StartTime, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.EditorFor(model => model.StartTime, new { htmlAttributes = new { @class = "form-control" } })
@Html.ValidationMessageFor(model => model.StartTime, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.EndTime, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.EditorFor(model => model.EndTime, new { htmlAttributes = new { @class = "form-control" } })
@Html.ValidationMessageFor(model => model.EndTime, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.Date, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.EditorFor(model => model.Date, new { htmlAttributes = new { @class = "form-control" } })
@Html.ValidationMessageFor(model => model.Date, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.Description, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.EditorFor(model => model.Description, new { htmlAttributes = new { @class = "form-control" } })
@Html.ValidationMessageFor(model => model.Description, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.Address, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.EditorFor(model => model.Address, new { htmlAttributes = new { @class = "form-control" } })
@Html.ValidationMessageFor(model => model.Address, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.State, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.EditorFor(model => model.State, new { htmlAttributes = new { @class = "form-control" } })
@Html.ValidationMessageFor(model => model.State, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
@Html.LabelFor(model => model.ZIP, htmlAttributes: new { @class = "control-label col-md-2" })
<div class="col-md-10">
@Html.EditorFor(model => model.ZIP, new { htmlAttributes = new { @class = "form-control" } })
@Html.ValidationMessageFor(model => model.ZIP, "", new { @class = "text-danger" })
</div>
</div>
<div class="form-group">
<div class="col-md-offset-2 col-md-10">
<input type="submit" value="Create" class="btn btn-default" />
</div>
</div>
</div>
}
<div>
@Html.ActionLink("Back to List", "Index")
</div>
@section Scripts {
@Scripts.Render("~/bundles/jqueryval")
}
以及它的控制器：
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 Dyad.GreenvilleFoodTrucks.Data;
namespace Dyad.GreenvilleFoodTrucks.Controllers
{
public class LocationsController : Controller
{
private GreenvilleFoodTrucksEntities db = new GreenvilleFoodTrucksEntities();
// GET: Locations
public ActionResult Index()
{
var locations = db.Locations.Include(l => l.Truck);
return View(locations.ToList());
}
// GET: Locations/Details/5
public ActionResult Details(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
Location location = db.Locations.Find(id);
if (location == null)
{
return HttpNotFound();
}
return View(location);
}
// GET: Locations/Create
public ActionResult Create()
{
ViewBag.TruckID = new SelectList(db.Trucks, "ID", "Name");
return View();
}
// POST: Locations/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,TruckID,StartTime,EndTime,Date,Description,Address,State,ZIP")] Location location)
{
if (ModelState.IsValid)
{
db.Locations.Add(location);
db.SaveChanges();
return RedirectToAction("Index");
}
ViewBag.TruckID = new SelectList(db.Trucks, "ID", "Name", location.TruckID);
return View(location);
}
// GET: Locations/Edit/5
public ActionResult Edit(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
Location location = db.Locations.Find(id);
if (location == null)
{
return HttpNotFound();
}
ViewBag.TruckID = new SelectList(db.Trucks, "ID", "Name", location.TruckID);
return View(location);
}
// POST: Locations/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,TruckID,StartTime,EndTime,Date,Description,Address,State,ZIP")] Location location)
{
if (ModelState.IsValid)
{
db.Entry(location).State = EntityState.Modified;
db.SaveChanges();
return RedirectToAction("Index");
}
ViewBag.TruckID = new SelectList(db.Trucks, "ID", "Name", location.TruckID);
return View(location);
}
// GET: Locations/Delete/5
public ActionResult Delete(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
Location location = db.Locations.Find(id);
if (location == null)
{
return HttpNotFound();
}
return View(location);
}
// POST: Locations/Delete/5
[HttpPost, ActionName("Delete")]
[ValidateAntiForgeryToken]
public ActionResult DeleteConfirmed(int id)
{
Location location = db.Locations.Find(id);
db.Locations.Remove(location);
db.SaveChanges();
return RedirectToAction("Index");
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
db.Dispose();
}
base.Dispose(disposing);
}
}
}
在处理完所有这些问题后，我想指出的是，当我以管理员身份运行VS时，这一切都没有发生，这一点我不太理解。此外，每个编译和运行都像往常一样。
对于我冗长的说明，我深表歉意，但我不想遗漏任何细节。如果我误用了任何术语，请谅解，因为我对MVC和C#还不够熟悉。
如果还有其他需要包含的内容，请告诉我。
Jim在这里的回答中所述？（https://dev59.com/7G445IYBdhLWcg3wO3xu） - Jonesopolis