.net mvc dropdownlist未更新

我有以下两种型号：

员工模式

public int ID{get;set;}
public string name{get;set;}
public virtual Department Department{get;set;}

部门模式

public int ID{get;set;}
public string name{get;set;}

在添加新员工时，我使用员工视图上的下拉列表

员工编辑控制器

public ActionResult Edit(employee employee)
{
   ....
   ViewBag.ID = new SelectList(db.departments,"ID","Name",employee.ID);
   return View(employee);
}

他认为：

@Html.DropDownList("ID")

添加新员工会正确保存部门，但当我编辑现有记录时，它不会保存

我忽略了什么

模型绑定：

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Entity;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using AssetManagement.Models;

namespace AssetManagement.Controllers
{
    public class EmployeeController : Controller
    {
        private AssetContext db = new AssetContext();

        //
        // GET: /Employee/

        public ActionResult Index()
        {
            var employees = db.Employees.Include(e => e.Department);
            return View(employees.ToList());
        }

        //
        // GET: /Employee/Details/5

        public ActionResult Details(int id = 0)
        {
            Employee employee = db.Employees.Find(id);
            if (employee == null)
            {
                return HttpNotFound();
            }
            return View(employee);
        }

        //
        // GET: /Employee/Create

        public ActionResult Create()
        {
            ViewBag.ID = new SelectList(db.Departments, "ID", "Name");
            return View();
        }

        //
        // POST: /Employee/Create

        [HttpPost]
        public ActionResult Create(Employee employee)
        {
            if (ModelState.IsValid)
            {
                db.Employees.Add(employee);
                db.SaveChanges();
                return RedirectToAction("Index");
            }

            ViewBag.ID = new SelectList(db.Departments, "ID", "Name", employee.ID);
            return View(employee);
        }

        //
        // GET: /Employee/Edit/5

        public ActionResult Edit(int id = 0)
        {
            Employee employee = db.Employees.Find(id);
            if (employee == null)
            {
                return HttpNotFound();
            }
            ViewBag.IDList = new SelectList(db.Departments, "ID", "Name", employee.ID);
            return View(employee);
        }

        //
        // POST: /Employee/Edit/5

        [HttpPost]
        public ActionResult Edit(Employee employee)
        {

            if (ModelState.IsValid)
            {
                db.Entry(employee).State = EntityState.Modified;
                db.SaveChanges();
                return RedirectToAction("Index");
            }
          ViewBag.IDList = new SelectList(db.Departments, "ID", "Name", employee.ID);

            return View(employee);
        }

        //
        // GET: /Employee/Delete/5

        public ActionResult Delete(int id = 0)
        {
            Employee employee = db.Employees.Find(id);
            if (employee == null)
            {
                return HttpNotFound();
            }
            return View(employee);
        }

        //
        // POST: /Employee/Delete/5

        [HttpPost, ActionName("Delete")]
        public ActionResult DeleteConfirmed(int id)
        {
            Employee employee = db.Employees.Find(id);
            db.Employees.Remove(employee);
            db.SaveChanges();
            return RedirectToAction("Index");
        }

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

公共课组{ 公共int ID{get；set；} 公共字符串名称{get；set；} 公共虚拟员工站点联系人{get；set；} 公共ICollection资产{get；set；} }

---

实体框架未保存，因为员工实体“Employee”（编辑帖子中的参数）不在上下文中。当您再次调用控制器时，先前的上下文将被销毁，并且该实体不在实际上下文中。Get和Post中的db上下文不同

因此，您必须搜索要编辑和修改的实体。之后，您可以保存您的实体

试试这个：

    [HttpPost]
    public ActionResult Edit(Employee employee)
    {

        if (ModelState.IsValid)
        {
            var employeeModify = db.Find(employee.Id);
            employeeModify.name = employee.Name;
            employeeModify.DepartamentId = employee.DepartamentId;
            db.SaveChanges();
            return RedirectToAction("Index");
        }
      ViewBag.IDList = new SelectList(db.Departments, "ID", "Name", employee.ID);

        return View(employee);
    }

---

好的，我有点困惑b/c似乎你要将部门列表绑定到Emp ID，但这是我对你的回答的最好理解。我有一个部门集合，我希望在添加新员工时能够选择一个部门。好的，我看到了你的控制器。但是，你正在调用哪种操作，你在视图中绑定了什么模型？我已经添加了员工模型，但仍在尝试，我将在一个小时左右回复你

    [HttpPost]
    public ActionResult Edit(Employee employee)
    {

        if (ModelState.IsValid)
        {
            var employeeModify = db.Find(employee.Id);
            employeeModify.name = employee.Name;
            employeeModify.DepartamentId = employee.DepartamentId;
            db.SaveChanges();
            return RedirectToAction("Index");
        }
      ViewBag.IDList = new SelectList(db.Departments, "ID", "Name", employee.ID);

        return View(employee);
    }