Question

我有从数据库检索的实体类：

public class User{
    public string Username {get; set;}
    public List<IAddress> Addresses {get; set;}
}

public class Address: IAddress{
    public string Line1 {get; set;}
    public string Line2 {get; set;}
}
public class AddressExtended:Address, IAddress{
    public string Line3 {get; set;}
    public string Line4 {get; set;}
}
public interface IAddress{
}

我使用Automapper将此实体映射到镜像的DTO：

public class UserDto{
    [JsonProperty("username")]
    public string Username { get; set; }
    [JsonProperty("addresses")]
    public List<IAddressDto> Addresses { get; set; }
}

public class AddressDto: IAddressDto{
    [JsonProperty("line1")]
    public string Line1 { get; set; }
    [JsonProperty("line2")]
    public string Line2 { get; set; }
}
public class AddressExtendedDto:AddressDto, IAddressDto{
    [JsonProperty("line3")]
    public string Line3 { get; set; }
    [JsonProperty("line4")]
    public string Line4 { get; set; }
}
public interface IAddressDto{
}

Automapper配置如下：

CreateMap<IAddress, IAddressDto>();
CreateMap<Address, AddressDto>();
CreateMap<AddressExtended, AddressExtendedDto>();

问题是，当我运行应用程序时，如果在实体中我有2个地址和1个AddressExtended，则在DTO中，Addresses属性（）的映射方式如下：

[   
 {Proxy<MyProject.Models.Dto.IAddressDto_MyProject_Version=1.0.0.0_Culture=neutral_PublicKeyToken=null>},
 {Proxy<MyProject.Models.Dto.IAddressDto_MyProject_Version=1.0.0.0_Culture=neutral_PublicKeyToken=null>},
 {Proxy<MyProject.Models.Dto.IAddressDto_MyProject_Version=1.0.0.0_Culture=neutral_PublicKeyToken=null>}
]

正确设置了Username属性的值。

我想念什么？

UPDATE

我在这里添加了提琴手：

https://dotnetfiddle.net/ZkUZgp

Answer 1

据我所知，解决该问题的一种方法是使用以下代码构建

cfg.CreateMap<Address, AddressDto>();
cfg.CreateMap<AddressExtended, AddressExtendedDto>();
cfg.CreateMap<IAddress, IAddressDto>().ConstructUsing((IAddress addressDto) =>
{
    if (addressDto is AddressExtended) return Mapper.Map<AddressExtendedDto>(addressDto);
    return Mapper.Map<AddressDto>(addressDto);
});

编辑1：这是最终答案，它可以解决您的问题

cfg.CreateMap<Address, AddressDto>();
cfg.CreateMap<AddressExtended, AddressExtendedDto>();
cfg.CreateMap<IAddress, IAddressDto>().ConstructUsing((addressDto, ctx) =>
{
    var destination = Mapper.Instance.ConfigurationProvider.GetAllTypeMaps()
                        .First(t => t.SourceType == addressDto.GetType());
    return ctx.Mapper.Map(addressDto, addressDto.GetType(), destination.DestinationType) as IAddressDto;
});

代替使用LINQ获取目标类型，您可以构建字典并从中获取字典以更快地执行。

使用接口将实体映射到dto

1 个答案: