Is there a general way to use AutoMapper ValueResolver to map EntityKey values ​​for EF objects?

Question

Not sure if it makes sense, but here's what I do. I use AutoMapper to map Entity Framework objects to DTO objects and vice versa. The problem occurs when I try to map DTO data to an EF object. There is no property mapping property for EntityKey. To fix this, I do the following:

        Mapper.CreateMap<VideoDTO, Video>()
            .ForMember(dest => dest.EntityKey, opt =>   
opt.ResolveUsing<VideoEntityKeyResolver>());

The VideoEntityKeyResolver class is as follows:

public class VideoEntityKeyResolver : ValueResolver<VideoDTO, EntityKey>
{
    protected override EntityKey ResolveCore(VideoDTO source)
    {
        EntityKey key = new EntityKey("EntityFrameworkTestingEntities.Videos",
            "VideoId", source.VideoId);
        return key;
    }
}

I was wondering if there was a more general way to do this when I could have 1 class with a constructor that accepts the name of the set of objects, the key name of the property, and the key value in the constructor.

EntityKey DTO, , , DTO , .

( ), AutoMapper? ( EF), , , .

Answer 1

, , :

public class EntityKeyResolver<T, TProperty> : ValueResolver<T, EntityKey> where T : class
{
    private Expression<Func<T, TProperty>> _propertyExpression;
    private string _qualifiedEntitySetName;
    private string _keyName;

    public EntityKeyResolver(string qualifiedEntitySetName, string keyName, Expression<Func<T, TProperty>> propertyExpression)
    {
        _qualifiedEntitySetName = qualifiedEntitySetName;
        _keyName = keyName;
        _propertyExpression = propertyExpression;
    }

    protected override EntityKey ResolveCore(T source)
    {
        return new EntityKey(_qualifiedEntitySetName, _keyName, ExpressionHelper.GetValue(_propertyExpression));
    }
}

ExpressionHelper - , . GetValue :

internal static TProperty GetValue<T, TProperty>(T obj, Expression<Func<T, TProperty>> expression) where T : class
{
    if (obj == null)
    {
        return default(TProperty);
    }

    Func<T, TProperty> func = expression.Compile();

    return func(obj);
}

(, VideoId ):

Mapper.CreateMap<VideoDTO, Video>()         
            .ForMember(dest => dest.EntityKey, opt => opt.ResolveUsing(new EntityKeyResolver<VideoDTO, Guid>("EntityFrameworkTestingEntities.Videos", "VideoId", v => v.VideoId)));

, , . MapFrom ( ):

Mapper.CreateMap<VideoDTO, Video>()         
                .ForMember(dest => dest.EntityKey, opt => opt.MapFrom(src => new EntityKey("EntityFrameworkTestingEntities.Videos", "VideoId", src.VideoId)));

, , , , AppDomain. , , MapInitializer.EnsureMaps();