ASP.NET MVC什麼是使用ViewModels的最佳方式？

Question

Customers.cs

public partial class Customers 
{ 
    public int sno { get; set; } 
    public string CustomerName { get; set; } 
    public string CustomerNo { get; set; } 
    ... 
    // 20 more attribute too... 
} 

Cities.cs

public partial class Cities 
{ 
    public int sno { get; set; } 
    public string CityName { get; set; } 
    public string CityPlate { get; set; } 
    public string CityPhoneCode { get; set; } 
} 

AddCustomerViewModel.cs

public class AddCustomerViewModel 
{ 

    [Required(ErrorMessage = "Şehir seçiniz.")] 
    [Display(Name = "Şehir")] 
    public Nullable<int> CityId { get; set; } 

    // same with Customers.cs 
    public int sno { get; set; } 

    [Required(ErrorMessage = "Müşteri adını giriniz!")] 
    [Display(Name = "Müşteri Adı")] 
    public string CustomerName { get; set; } 

    [Required(ErrorMessage = "Müşteri numarası giriniz!")] 
    [Display(Name = "Müşteri Numarası")] 
    public string CustomerNo { get; set; } 
    ... 
    // 20 more attribute too... 
} 

控制器

[Authorize(Roles = "Administrator")] 
public ActionResult AddCustomer() 
{ 
    AddCustomerViewModel addCustomerViewModel = new AddCustomerViewModel(); 
    addCustomerViewModel.Cities = entity.Cities; 

    return View(addCustomerViewModel); 
} 

[HttpPost] 
[Authorize(Roles = "Administrator")] 
public ActionResult AddCustomer(AddCustomerViewModel addCustomerViewModel) 
{ 
    entity.Customers.Add(GetCustomerFromViewModel(addCustomerViewModel)); 
    entity.SaveChanges(); 

    return View(addCustomerViewModel); 
} 

我米使用被稱爲GetCustomerFromViewModel到addCustomerViewModel轉換爲客戶像下面的函數：）

GetCustomerFromViewModel（

private Customers GetCustomerFromViewModel(AddCustomerViewModel addCustomerViewModel) 
{ 
    Customers customer = new Customers(); 

    customer.CityId = addCustomerViewModel.CityId; 
    customer.CreatorUserId = (Guid)System.Web.Security.Membership.GetUser().ProviderUserKey; 
    customer.CustomerName = addCustomerViewModel.CustomerName; 
    customer.CustomerNo = addCustomerViewModel.CustomerNo; 
    customer.Description = addCustomerViewModel.Description; 
    ... 
    // 20 more attribute too... 

    return customer; 
} 

但客戶類有太多的變量（customerNo，客戶名稱，...），所以這是不好的方法。

當我使用DbContextGenerator並將類添加到dataAnnotations，然後當我更新模型時，dataAnnotations被刪除。 （因爲DbContext類也被更新）

如何在DataAnnotations中使用ViewModels。對Db有效插入操作？文章，教程，示例或建議？

我希望我能解釋一下。

非常感謝......

Answer 1

你可以看看AutoMapper，這將簡化您的域模型和視圖模型之間的映射邏輯，這樣你就不需要每個屬性手動映射。除此之外，您的代碼沒有任何問題。您已經在使用視圖模型並具有映射圖層。所以你GetCustomerFromViewModel功能可能會成爲：

private Customers GetCustomerFromViewModel(AddCustomerViewModel addCustomerViewModel) 
{ 
    return Mapper.Map<AddCustomerViewModel, Customers>(addCustomerViewModel); 
} 

或完全擺脫它，並直接使用AutoMapper呼叫控制器操作，因爲此功能不再帶來多少價值：

[HttpPost] 
[Authorize(Roles = "Administrator")] 
public ActionResult AddCustomer(AddCustomerViewModel addCustomerViewModel) 
{ 
    var customer = Mapper.Map<AddCustomerViewModel, Customers>(addCustomerViewModel); 
    entity.Customers.Add(customer); 
    entity.SaveChanges(); 

    return View(addCustomerViewModel); 
}