使用接口将实体映射到dto

Question

I've my entity class I retrieve from database:

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{
}

I use Automapper to map this entity to the mirrored 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 configuration is the following:

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

The problem is that when I run my application, if in the entity I have 2 addresses and 1 addressExtended, in DTO the Addresses property () is mapped like this:

[   
 {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>}
]

The Username property it is correctly valued.

What I miss?

UPDATE

I added a fiddler here:

https://dotnetfiddle.net/ZkUZgp

Answer 1

As per my knowledge, one approach solving the issue is using Construct using below code

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);
});

Edit 1: Here is the final answer and it solves your problem

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;
});

Instead of getting destination type using LINQ you can build a dictionary and get from it for faster execution.