.NET C＃CRUD操作有效，但从未在数据库中更新

Question

我的创建和删除操作成功完成，没有任何错误，但什么都不做。当我尝试创建新产品并保存时，它不会显示在我的桌面上。当我尝试删除某个产品时，它不会被删除。

我认为问题出在我的InventoryContext.cs文件中：

public class InventoryContext : System.Data.Entity.DbContext

我必须为db.SaveChanges（）添加System.Data.Entity.DbContext以不显示错误。

当我编辑某些产品并保存时，它给了我这个：

ProductController.cs

    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 Inventory.DAL;
    using Inventory.Models;

    namespace Inventory.Controllers
    {
        public class ProductController : Controller
        {
            private InventoryContext db = new InventoryContext();

            // GET: Product
        public ActionResult Index()
        {
            return View(db.Products.ToList());
        }

        public ActionResult Details(int id)
        {
            Product product = db.Products.FirstOrDefault(c => c.Id == id);

            // there error handling should be better than this
            if (product == null)
                return HttpNotFound();

            return View(product);
        }

        // GET: Product/Edit/5
        public ActionResult Edit(int? id)
        {
            if (id == null)
            {
                return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
            }
            Product product = db.Products.FirstOrDefault(c => c.Id == id);
            if (product == null)
            {
                return HttpNotFound();
            }
            return View(product);
        }

        [HttpPost]
        [ValidateAntiForgeryToken]
        public ActionResult Edit([Bind(Include = "Id,CategoryId,Brand,Name,Barcode,Price")] Product product)
        {
            if (ModelState.IsValid)
            {
                db.Entry(product).State = EntityState.Modified;
                db.SaveChanges();
                return RedirectToAction("Index");
            }
            return View(product);
        }

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


        [HttpPost, ActionName("Create")]
        [ValidateAntiForgeryToken]
        public ActionResult Create([Bind(Include = "Id,CategoryId,Brand,Name,Barcode,Price")] Product product)
        {
            if (ModelState.IsValid)
            {
                db.Products.Add(product);
                db.SaveChanges();
                return RedirectToAction("Index");
            }

            return View(product);
        }


        public ActionResult Delete(int? id)
        {
            if (id == null)
            {
                return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
            }
            Product product = db.Products.FirstOrDefault(c => c.Id == id);
            if (product == null)
            {
                return HttpNotFound();
            }
            return View(product);
        }
        [HttpPost, ActionName("Delete")]
        [ValidateAntiForgeryToken]
        public ActionResult DeleteConfirmed(int id)
        {
            Product product = db.Products.FirstOrDefault(c => c.Id == id);
            db.Products.Remove(product);
            db.SaveChanges();
            return RedirectToAction("Index");
        }

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


        public ActionResult Assign(int productId, int categoryId)
        {
            Product product = db.Products.FirstOrDefault(p => p.Id == productId);
            product.CategoryId = categoryId;
            return RedirectToAction("Index");
        }


    }
}

InventoryContext.cs

using System.Collections.Generic;
using Inventory.Models;
using System.Linq;

namespace Inventory.DAL
{
    public class InventoryContext : System.Data.Entity.DbContext
    {
        public List<Product> Products { get; set; }
        public List<Category> Categories { get; set; }

        public InventoryContext()
        {
            Products = new List<Product>
            {
            new Product{Id=1,CategoryId=1,Brand="Coca Cola", Name="Coca Cola",Barcode="00001",Price=150},
            new Product{Id=2,CategoryId=1,Brand="Pepsi", Name="Pepsi",Barcode="00011",Price=150},
            new Product{Id=3,CategoryId=2,Brand="Homebrand", Name="Baked Beans",Barcode="0002",Price=250},
            new Product{Id=4,CategoryId=2,Brand="Homebrand", Name="Baked Patatos",Barcode="0022",Price=250}

            };
            Categories = new List<Category>
            {
            new Category{ID=1, Name="Drink", Products = Products.Where(p => p.CategoryId == 1).ToList() },
            new Category{ID=2,Name="Canned Food", Products = Products.Where(p => p.CategoryId == 2).ToList() }

            };
            foreach (var product in Products)
                product.Categories = Categories.Where(c => c.ID == product.CategoryId).ToList();

        }
    }
}

Answer 1

在InventoryContext.cs文件中，请通过添加以下行来检查。

public System.Data.Entity.DbSet Products {get; set;} public System.Data.Entity.DbSet Category {get; set;}

请参阅以下链接以获取解决方案。 http://www.asp.net/mvc/overview/older-versions/getting-started-with-aspnet-mvc4/adding-a-model