AutoMapper：深度属性映射+转换器

Question

每个端点都有很多自动生成的类似 API 模型（我无法更改！）并且喜欢映射到单个目的地。

例如，如果我想从 Dun&Bradstreet API 映射 IDRCleanseMatch.json 和 cmpelkv2.json 端点：

Api1.Organization → OrganizationDestinationModel
Api2.Organization → OrganizationDestinationModel

以下是源模型和目标模型：

namespace Api1
{
    public class Organization 
    {
        public string Duns { get; set; }
        public DunsControlStatus DunsControlStatus { get; set; }
        public string PrimaryName { get; set; }
        //...
    }
    public class DunsControlStatus 
    {
        public OperatingStatus OperatingStatus { get; set; }
        //...
    }
    public class OperatingStatus 
    {
        public string Description { get; set; }
        public int? DnbCode { get; set; }
        //...
    }
}
namespace Api2 { /* Same as above. */ }
public class OrganizationDestinationModel
{
    public string Duns { get; set; }
    public string Name { get; set; }
    public bool IsOutOfBusiness { get; set; }
}

我的方法是使用通用辅助方法：

config.MapToOrganizationDestinationModel<Api1.Organization>();
config.MapToOrganizationDestinationModel<Api2.Organization>();

private static void MapToOrganizationDestinationModel<TSource>(this IMapperConfigurationExpression config)
{
    config
        .CreateMap<TSource, OrganizationDestinationModel>()
        .ForMember(
            destination => destination.Name,
            options => options.MapFrom(nameof(Api1.Organization.PrimaryName))
        )
        // Doesn't work!!!
        // ArgumentException : 'DunsControlStatus.OperatingStatus.DnbCode' is not a member of type 'Core.Api1.Organization' (Parameter 'propertyOrFieldName')
        .ForMember(
            destination => destination.IsOutOfBusiness,
            options => options.ConvertUsing(
                new IsOutOfBusinessConverter(),
                $"{nameof(Api1.Organization.DunsControlStatus)}.{nameof(Api1.DunsControlStatus.OperatingStatus)}.{nameof(Api1.OperatingStatus.DnbCode)}"
            )
        )
        ;
}
public class IsOutOfBusinessConverter : IValueConverter<int?, bool>
{
    public bool Convert(int? code, ResolutionContext _) => code == 403;
}

但我完全被以下IsOutOfBusiness 映射所困扰！有没有机会将int? → bool 转换为字符串并将Organization.DunsControlStatus.OperatingStatus.DnbCode 指向我的“非类型化”映射。

Answer 1

就像ConvertUsing 方法不接受导航属性方案一样。也许你可以在 lambda 中使用其他 ForMember 的重载和导航属性：

.ForMember(
    d => d.IsOutOfBusiness,
    opts => opts.MapFrom(s => (s.Organization.DunsControlStatus.OperatingStatus.DnbCode ?? 0) == 403)
)

您可以在文档中找到其他示例：Custom Value Resolvers

在您的情况下，源类型未知。您可以使用反射导航到 DnbCode ：

private static void MapToOrganizationDestinationModel<TSource>(this IMapperConfigurationExpression config)
{
    config
        .CreateMap<TSource, OrganizationDestinationModel>()
        ...
        .ForMember(
            destination => destination.IsOutOfBusiness,
            opts => opts.MapFrom(org => (org.DnbCode() ?? 0) == 403)
        );
}

private static int? DnbCode(this object org)
{
    var dcs = org.GetType().GetProperty(nameof(Api1.Organization.DunsControlStatus)).GetValue(org);
    var oss = dcs.GetType().GetProperty(nameof(Api1.DunsControlStatus.OperatingStatus)).GetValue(dcs);
    var dnb = oss.GetType().GetProperty(nameof(Api1.OperatingStatus.DnbCode)).GetValue(oss);
    return dnb as int?;
}

AutoMapper 可能存在更优雅的方式，但我没有找到...

Answer 2

我了解您喜欢将ValueConverter 与ConvertUsing 一起使用，但如果您可以修改目标模型（我希望可以这样做）并且不使用ValueConverter，您可以获得相同的结果：

通过添加新属性DnbCode 更新目标模型并修改IsOutOfBusiness 如下

public class OrganizationDestinationModel
{
    public string Duns { get; set; }
    public string Name { get; set; }
    public int? DnbCode { get; set; }
    public bool IsOutOfBusiness { get { return (DnbCode ?? 0) == 403;  } }
}

更新MapToOrganizationDestinationModel 方法以映射新属性DnbCode 如下

    public static void MapToOrganizationDestinationModel<T>(this IMapperConfigurationExpression config)
    {
        config
            .CreateMap<T, OrganizationDestinationModel>()
            .ForMember(
                destination => destination.Name,
                options => options.MapFrom(nameof(Api1.Organization.PrimaryName))
            )
            .ForMember(
                destination => destination.DnbCode,
                opts => opts.MapFrom("DunsControlStatus.OperatingStatus.DnbCode")
            );
    }

完成.. IsOutOfBusiness 属性不需要映射

Answer 3

我会建议这个解决方案：

private static void MapToOrganizationDestinationModel<TSource>(this IMapperConfigurationExpression config)
{
    //source
    var source = Expression.Parameter(typeof(TSource), "source");
    //source.DunsControlStatus
    var body = Expression.Property(source, nameof(Api1.Organization.DunsControlStatus));
    //source.DunsControlStatus.OperatingStatus
    body = Expression.Property(body, nameof(Api1.DunsControlStatus.OperatingStatus));
    //source.DunsControlStatus.OperatingStatus.DnbCode
    body = Expression.Property(body, nameof(Api1.OperatingStatus.DnbCode));
    //source => source.DunsControlStatus.OperatingStatus.DnbCode
    var dnbCodeSelector = Expression.Lambda<Func<TSource, int?>>(body, source);

    config
        .CreateMap<TSource, OrganizationDestinationModel>()
        .ForMember(
            destination => destination.Name,
            options => options.MapFrom(nameof(Api1.Organization.PrimaryName))
        )
        .ForMember(
            destination => destination.IsOutOfBusiness,
            options => options.MapFrom(
                new IsOutOfBusinessMemberValueResolver<TSource>(),
                dnbCodeSelector //source => source.DunsControlStatus.OperatingStatus.DnbCode
                )
        );
}

我承认dnbCodeSelector 的组成确实很丑，但这是保持目标模型不变并将ValueResolver 简化为可重复使用的“转换器”的唯一方法：

public class IsOutOfBusinessMemberValueResolver<TSource> : IMemberValueResolver<TSource, object, int?, bool>
{
    public bool Resolve(TSource source, object destination, int? sourceMember, bool destMember, ResolutionContext context)
    {
        return sourceMember == 403;
    }
}

也许 AutoMapper 可以在未来的版本中简化此解决方案？