MVC实现增删查改

1.添加Northwind.edmx（ADO.NET Entity Data Model）.

2. 在HomeController中添加如下代码：

    [HandleError]
    public class HomeController : Controller
    {
        NorthwindEntities NorthWind = new NorthwindEntities();
        public ActionResult Index()
        {
            var model = NorthWind.Categories.ToList();
            return View(model);
        }
        [AcceptVerbs(HttpVerbs.Get)]
        public ActionResult Edit(int id)
        {
            // 返回集合中的第一个元素，其实质就是在SQL语句中加TOP (1)。
            var model = NorthWind.Categories.First(c => c.CategoryID == id);
            return View(model);
        }
        [AcceptVerbs(HttpVerbs.Post)]
        public ActionResult Edit(int id,FormCollection form)
        {
            var model = NorthWind.Categories.First(c => c.CategoryID == id);
            UpdateModel(model,new []{"CategoryName","Description"});
            NorthWind.SaveChanges();
            return RedirectToAction("Index");
        }
        [AcceptVerbs(HttpVerbs.Get)]
        public ActionResult Details(int id)
        {
            var model = NorthWind.Categories.First(c => c.CategoryID == id);
            return View(model);
        }
        [AcceptVerbs(HttpVerbs.Get)]
        public ActionResult Create()
        {
            Categories categories=new Categories();
            return View(categories);
        }
        [AcceptVerbs(HttpVerbs.Post)]
        public ActionResult Create(int CategoryID,FormCollection form)
        {
            //当序列中可能找不到满足条件的元素时，使用FirstOrDefault方法，然后，一定要对返回值是否为null，进行不同的处理
            var model = NorthWind.Categories.FirstOrDefault(c => c.CategoryID == CategoryID);
            if (model==null)
            {
                Categories categories=new Categories();
                UpdateModel(categories,new[]{"CategoryName","Description"});
                NorthWind.AddToCategories(categories);
                NorthWind.SaveChanges();
                return RedirectToAction("Index");
            }
            else
            {
                return RedirectToAction("Create");
            }
        }
        public ActionResult About()
        {
            return View();
        }
    }

3.在Index处右键,然后Add View,如下图：

 

4. 用以上方法依次添加增删查改