Use Automapper to hide database primary key/ID (convert member with ValueConverter) - entity-framework-core

Question

I am trying to hide the real Ids of the objects in a database using Automapper's value converters, however they are not called when projecting one to the other.
Nothing special, I would like to use Hashids to convert the int ID to a random string ID (DB->DTO) and vice versa. I want to do this for every object and every ID, but instead of my converter getting called the id's in the database simply get converted strings (so 1 would become "1" instead of for example "sd2+a!F").
My Class:
public class Category
{
public Category(string name)
{
Name = name;
}
public int Id { get; set; }
public string Name { get; set; }
public int? ParentCategoryId { get; set; }
public Category? ParentCategory { get; set; }
public ICollection<Foodstuff> Foodstuffs { get; } = new List<Foodstuff>();
public ICollection<int> FoodstuffIds { get; } = new List<int>();
public byte[] RowVersion { get; set; }
}
My DTO:
public record class Category : IGenerateETag
{
public Category(string name)
{
Name = name;
}
public string Id { get; init; }
[Required(ErrorMessage = "Category name is required.", AllowEmptyStrings = false)]
public string Name { get; init; }
public string? ParentCategoryId { get; init; }
public byte[] RowVersion { get; set; }
}
My converters:
public class HideIdConverter : IValueConverter<int, string>
{
public string Convert(int sourceMember, ResolutionContext context)
{
var hashids = new Hashids();
var shadow = hashids.Encode(sourceMember);
return shadow;
}
}
public class UnhideIdConverter : IValueConverter<string, int>
{
public int Convert(string sourceMember, ResolutionContext context)
{
var hashids = new Hashids();
var plain = hashids.Decode(sourceMember);
return plain[0]; // TODO check this;
}
}
Aaand my Automapper config:
CreateMap<Dal.Entities.Category, Category>()
.ForMember(dest => dest.Id, opt => opt.ConvertUsing(new HideIdConverter(), src => src.Id))
.ReverseMap()
.ForMember(dest => dest.Id, opt => opt.ConvertUsing(new UnhideIdConverter(), src => src.Id));

Answer 1

It turns out that it this is not possible, because I was using LINQ expressions, especially ProjectTo(). It is stated that:
Value converters are only used for in-memory mapping execution. They will not work for ProjectTo.
Source.
I guess I will have to map the objects after I queried them from my database.