AutoMapper平面化嵌套集合
本文关键字:集合 嵌套 平面化 AutoMapper | 更新日期: 2023-09-27 18:01:27
我试图弄清楚如何将包含订单的商户集合扁平化到OrderViewModels的扁平列表。
这里是我的DTO:
public class Merchant
{
public string MerchantName { get; set; }
public List<Order> Orders { get; set; }
}
public class Order
{
public string OrderId { get; set; }
}
这里是视图模型:
public class OrderViewModel
{
public string MerchantName { get; set; }
public string OrderId { get; set; }
}
我的目标是将List
var myMerchants = new List<Merchant>
{
new Merchant
{
MerchantName = "Merchant X",
Orders = new List<Order>
{
new Order { OrderId = "Order 1"},
new Order { OrderId = "Order 2"},
new Order { OrderId = "Order 3"}
}
},
new Merchant
{
MerchantName = "Merchant Y",
Orders = new List<Order>
{
new Order { OrderId = "Order 4"},
new Order { OrderId = "Order 5"},
new Order { OrderId = "Order 6"}
}
}
};
var models = Mapper.Map<List<OrderViewModel>>(myMerchants);
因为根对象的基数不是1:1,(即2个根Merchants
需要映射到6个OrderViewModels
),您可能需要求助于自定义TypeConverter
并在集合级别操作,在那里您可以使用.SelectMany
来进行平坦化:
public class MyTypeConverter : ITypeConverter<IEnumerable<Merchant>, List<OrderViewModel>>
{
public List<OrderViewModel> Convert(ResolutionContext context)
{
if (context == null || context.IsSourceValueNull)
return null;
var source = context.SourceValue as IEnumerable<Merchant>;
return source
.SelectMany(s => s.Orders
.Select(o => new OrderViewModel
{
MerchantName = s.MerchantName,
OrderId = o.OrderId
}))
.ToList();
}
}
你可以引导它:
Mapper.CreateMap<IEnumerable<Merchant>, List<OrderViewModel>>()
.ConvertUsing<MyTypeConverter>();
然后映射为:
var models = Mapper.Map<List<OrderViewModel>>(myMerchants);
一个有趣的发现是,只要做下面的事情就足以实现目标,而不需要自动器。
var models = myMerchants.SelectMany(s => s.Orders.Select(o => new OrderViewModel { MerchantName = s.MerchantName, OrderId = o.OrderId })).ToList();
老问题,但认为对新版本有帮助。
我正在使用。net core 2和automapper。我更喜欢做ProjectTo扩展queryable
queryable
.SelectMany(outterClass => outterClass.innerList)
.AsQueryable()
.ProjectTo<OutterClassDto>();
然后,像这样配置:
config.CreateMap<OuterClass, OuterClassDto>();
还可以将SelectMany与AutoMapper结合起来,并对扁平集合中的每个项进行映射。这个Merchant需要两个映射->OrderViewModel和Order ->OrderViewModel
var models = myMerchants.SelectMany(s => s.Orders.Select(o =>
{
var mappedItem = Mapper.Map<OrderViewModel>(s);
Mapper.Map(o, mappedItem);
return mappedItem;
})).ToList();