asp.net-mvc – 将Viewmodel数据保存到ASP.NET MVC中的数据库

我是ASP.net MVC的新手,我使用viewmodel而不是viewbags填充我的下拉菜单,因为我看到大多数人推荐他们.我有一个光滑的用户界面,可以进行级联下拉和自动填充(此处未显示),但我似乎无法将我的数据保存回数据库.

楷模：

public partial class Car
    {
        public int CarID { get; set; }
        public string CarName { get; set; }
        public int ModelID { get; set; }
        public int ManufacturerID { get; set; }
        public int CarColorID { get; set; }
        public Nullable<decimal> Price { get; set; }
        public string Description { get; set; }

        public virtual CarColor CarColor { get; set; }
        public virtual Manufacturer Manufacturer { get; set; }
        public virtual CarModel CarModel { get; set; }
    }
   public partial class CarColor
    {
        public CarColor()
        {
            this.Cars = new HashSet<Car>();
        }

        public int ColorID { get; set; }
        public string ColorName { get; set; }

        public virtual ICollection<Car> Cars { get; set; }
    }
   public partial class CarModel
    {
        public CarModel()
        {
            this.Cars = new HashSet<Car>();
        }

        public int CarModelID { get; set; }
        public int ManufacturerID { get; set; }
        public string CarModelName { get; set; }

        public virtual ICollection<Car> Cars { get; set; }
        public virtual Manufacturer Manufacturer { get; set; }
    }
   public partial class Manufacturer
    {
        public Manufacturer()
        {
            this.Cars = new HashSet<Car>();
            this.Manufacturer1 = new HashSet<Manufacturer>();
            this.CarModels = new HashSet<CarModel>();
        }

        public int ManufacturerID { get; set; }
        public string ManufacturerName { get; set; }
        public Nullable<int> ParentID { get; set; }

        public virtual ICollection<Car> Cars { get; set; }
        public virtual ICollection<Manufacturer> Manufacturer1 { get; set; }
        public virtual Manufacturer Manufacturer2 { get; set; }
        public virtual ICollection<CarModel> CarModels { get; set; }
    }

视图模型：

public class AnotherTestviewmodel
    {
        public Car car { get; set; }

        public IEnumerable<SelectListItem> CarModels { get; set; }
        public IEnumerable<SelectListItem> Manufacturers { get; set; }
        public IEnumerable<SelectListItem> CarColors { get; set; }
    }

控制器：

public ActionResult Create()
        {
            var model = new AnotherTestviewmodel();
            using (new CarTestEntities())
            {
                model.CarModels = db.CarModels.ToList().Select(x => new SelectListItem
                {
                    Value = x.CarModelID.ToString(),Text = x.CarModelName
                });
                model.Manufacturers = db.Manufacturers.ToList().Select(x => new SelectListItem
                {
                    Value = x.ManufacturerID.ToString(),Text = x.ManufacturerName
                });
                model.CarColors = db.CarColors.ToList().Select(x => new SelectListItem
                {
                    Value = x.ColorID.ToString(),Text = x.ColorName
                });
            }
            return View(model);
        } 

        //
        // POST: /AnotherTest/Create

        [HttpPost]
        public ActionResult Create(AnotherTestviewmodel model)
        {
                if (ModelState.IsValid)
                {
                    db.Entry(model).State = EntityState.Modified;
                    db.SaveChanges();
                    return RedirectToAction("Details","AnotherTestviewmodel",new { id = model.car.CarID });
                }
                return View();
        }

我看到了一些使用Automapper的建议,因为EntityState.Modified不起作用,但我不知道如何配置它,因为使用下面的代码不起作用.

Mapper.CreateMap<AnotherTestviewmodel,Car>();
Mapper.CreateMap<Car,AnotherTestviewmodel>();
var newCar = Mapper.Map<AnotherTestviewmodel,Car>(model);

有任何想法吗？

解决方法

您的视图模型不应与数据库交互.视图模型应仅用于表示层(用户界面) – 因此称为“视图”模型.您应该有另一个与数据库交互的模型(数据模型).然后,您应该有一些类型的服务层来处理视图模型和数据模型之间的转换(反之亦然).您的数据模型是由Entity Framework生成的模型(我假设您正在使用它).要处理数据库更新,您需要实例化数据上下文,从数据库中获取数据实体,对该实体进行更改,并在该数据上下文中调用保存更改.数据上下文将跟踪实体的所有更改,并在您调用“保存更改”时对数据库应用必要的更改.
例：

public void UpdateCar(Carviewmodel viewmodel)
{
    using (DataContext context = new DataContext())
    {
        CarEntity dataModel = context.CarEntities.where(x => x.Id == viewmodel.Id).First();

        dataModel.Name = viewmodel.Name;
        dataModel.Type = viewmodel.Type;

        context.SaveChanges();
    }
}

在此示例中,上下文将跟踪对“dataModel”的任何更改.调用“context.SaveChanges”时,这些更改将自动应用于数据库.

asp.net-mvc – 将Viewmodel数据保存到ASP.NET MVC中的数据库

解决方法

猜你在找的asp.Net相关文章