我见过this question,this和this,但是以下错误并未消失:
当IDENTITY_INSERT设置为OFF时,无法为表“产品”中的标识列插入显式值。
我尝试过的是:
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
此外,我尝试将其设置为None
:
[DatabaseGenerated(DatabaseGeneratedOption.None)]
public int Id { get; set; }
T-SQL
代码如下:
CREATE TABLE Orders
(
Id INT IDENTITY(1,1),
DatePlaced datetime NOT NULL,
CONSTRAINT PK_Order_Id PRIMARY KEY (Id)
)
CREATE TABLE OrderItems
(
Id INT IDENTITY(1,1),
IdOrder INT NOT NULL
CONSTRAINT FK_OrderItems_IdOrder__Orders_Id FOREIGN KEY(IdOrder) REFERENCES Orders(Id),
IdProduct INT NOT NULL
CONSTRAINT FK_OrderItems_IdProduct__Products_Id FOREIGN KEY(IdProduct) REFERENCES Products(Id),
Quantity INT NOT NULL,
TotalPrice decimal (18,2),
CONSTRAINT PK_OrderItem_Id PRIMARY KEY (Id)
)
CREATE TABLE Products
(
Id INT IDENTITY(1,1),
Name varchar(100),
CONSTRAINT PK_Product_Id PRIMARY KEY (Id)
)
模型类如下:
public partial class Order
{
public Order()
{
OrderItems = new HashSet<OrderItem>();
}
public int Id { get; set; }
public DateTime DatePlaced { get; set; }
public virtual ICollection<OrderItem> OrderItems { get; set; }
}
public partial class OrderItem
{
public int Id { get; set; }
public int Quantity { get; set; }
[Column(TypeName = "decimal(18,2)")]
public decimal? TotalPrice { get; set; }
public virtual Order Order { get; set; }
public virtual Product Product { get; set; }
}
public partial class Product
{
public Product() { }
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
public string Name { get; set; }
}
和Customer
模型:
public class Customer : IdentityUser
{
public string FirstName { get; set; }
public string LastName { get; set; }
public virtual ICollection<Order> Orders { get; set; }
}
我想要保存Order
和OrderItems
。保存代码如下:
public async Task Add(Order order)
{
order.Customer = _context.Customers.Find(order.Customer.Id);
await _context.AddAsync(order);
await _context.SaveChangesAsync();
}
和OrderService
类:
public async Task<OrderDto> Add(OrderDto orderDto)
{
var order = _mapper.Map<Order>(orderDto);
await _orderRepository.Add(order);
orderDto.Id = order.Id;
return orderDto;
}
请告诉我我做错了什么?请不要关闭我的问题,因为它不是重复的。
答案 0 :(得分:0)
此行为的原因是Automapper
创建了一个新实例,并且实体框架认为POCO都是应该插入的所有新实体。
因此解决方案是将Attach
现有实体添加到`DbContext。 It is described in great tutorial here。
所以解决方案如下:
public async Task Add(Order order)
{
_context.Attach(order.Customer);
foreach (var orderItem in order.OrderItems)
{
_context.Attach(orderItem.Product);
}
await _context.Orders.AddAsync(order);
}
整个代码看起来像这样。
服务层:
public async Task<OrderDto> Add(OrderDto orderDto)
{
var order = _mapper.Map<Order>(orderDto);
await _orderRepository.Add(order);
orderDto.Id = order.Id;
return orderDto;
}
存储层:
public async Task Add(Order order)
{
_context.Attach(order.Customer);
foreach (var orderItem in order.OrderItems)
{
_context.Attach(orderItem.Product);
}
await _context.Orders.AddAsync(order);
}
答案 1 :(得分:0)
另一种解决方案是使用_mapper.Map(sourceProperty, destinationProperty);
。这不会更改参考。但是,在设置配置时,请确保忽略您不想映射的属性(即主键)。
例如在映射配置文件类的构造函数下:
CreateMap<SourceType, DestinationType>()
.ForMember(destination => destination.PK, options => options.Ignore());