ASP.NET MVC What is the best way to use ViewModels? - asp.net-mvc

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...
}
Controller
[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);
}
I m using a function that is called GetCustomerFromViewModel to convert addCustomerViewModel to Customer like below:
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;
}
But Customers class have too many variable (customerNo, CustomerName, ...) , So this is the not good way.
When I use DbContextGenerator and Add classes to dataAnnotations and then When I udated the model, dataAnnotations is deleted. (Because DbContext classes are updated, too)
How Can I use ViewModels with DataAnnotations. And effective insert operation to Db? Article, Tutorial, example or advice?
I hope I can explain.
Thanks a lot...

Answer 1

You may take a look at AutoMapper which will simplify the mapping logic between your domain models and view models so that you don't need to manually map each property. Other than that there's nothing wrong with your code. You are already using a view model and have a mapping layer. So your GetCustomerFromViewModel function might become:
private Customers GetCustomerFromViewModel(AddCustomerViewModel addCustomerViewModel)
{
return Mapper.Map<AddCustomerViewModel, Customers>(addCustomerViewModel);
}
or completely get rid of it and directly use the AutoMapper call in your controller action because this function no longer brings much value:
[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);
}