Question

我们有Customer事务表，其中包含多个带外键的查找表。我们希望看到3个表连接在一起并将ViewModel绑定回Model并反向。我听说存储库不应该访问ViewModels。

（a）中这样做的适当软件协议是什么？我还不想使用AutoMapper。我应该创建一个数据访问对象或服务，有人可以在下面为我写一个快速样本吗？我应该在MVC中创建另一个名为Data Service的文件夹吗？我买了3本MVC书籍，但没有人讨论DTO或绑定模型＆lt; - ＆gt;的ViewModels。谢谢，

存储库：

void GetByCustomerTransactionId()
{
   var result = from ct in CustomerTransaction
    join pt in ProductType on pt.ProductTypeId equals ct.ProductTypeId 
    join ss in Status on s.StatusId equals ct.StatusId 
    select new all fields
}

模特：

public class CustomerTransaction
{
    public int CustomerTransactionId{ get; set; },
    public int ProductTypeId {get; set; }, //joins to ProductTypeTable
    public int StatusID {get; set; },  //joins to StatusTypeTable
    public string DateOfPurchase{ get; set; },
    public int PurchaseAmount { get; set; },
}

public class ProductType
{
    public int ProductTypeId{ get; set; }
    public string ProductName { get; set; },
    public string ProductDescription { get; set; },
}

public class StatusType
{
    public int StatusId{ get; set; }
    public string StatusName{ get; set; },
    public string Description{ get; set; },

}

视图模型：

public class CustomerTransactionViewModel
    {
        public int CustomerTransactionId{ get; set; },
        public string ProductName {get; set; }, //joins to ProductTypeTable
        public string ProductDescription {get; set; }, 
        public string StatusName {get; set; },  //joins to StatusTable
        public string DateOfPurchase{ get; set; },
        public int PurchaseAmount { get; set; },
    }

Answer 1

您是否考虑将AutoMapper映射到数据库对象以查看模型。是非常整洁干净的方式。

如果您不想使用AutoMapper，可能需要考虑使用静态方法。

var student = new Student { FirstName = "John", LastName = "Doe" };
var mdoel = student.ToDTO();

public static StudentViewModel ToDTO(this Student student)
{
    var model = new StudentViewModel();
    model.FullName = $"{student.FirstName} {student.LastName}";
    return model;
}

希望这能帮到你

Answer 2

 public class CustomerTransactionViewModel : IViewModel
{
    public int CustomerTransactionId{ get; set; },
    public string ProductName {get; set; }, //joins to ProductTypeTable
    public string ProductDescription {get; set; }, 
    public string StatusName {get; set; },  //joins to StatusTable
    public string DateOfPurchase{ get; set; },
    public int PurchaseAmount { get; set; },
  // Every view model should always have mapper from dbmodel to vm.
  private void MaptoEntity(Entity e)
  {
    this.CustomerTransactionId = e.ID
    .....
    // this is also a repository that mapping db to view model.
    var prod = new ProductTypeViewModel().Load(e.ProductID);
    this.ProductName = prod.ProductName;
    this.ProductDescription = prod.ProductDescription;
    // so on.......
  }

  public bool Load(int id)
  {
   // Call data from DB.
    var entity = dbcontext.Entity.Find(id);
   // Map you from DB.
    this.MaptoEntity(entity)
  }
}

更好的结构是创建一个需要所有实现的接口IViewModel。

现在你可以打电话了

var customerViewModel = new CustomerTransactionViewModel();
customerViewModel .Load(1);

MVC Core将ViewModel绑定到Model

2 个答案: