Using ValueOf with Entity Framework Core?

Hi, I’m trying to incorporate your excellent library into my EFCore model classes, for example:

    public partial class Account
    {
        public Account()
        {
            WorkerGroups = new HashSet<WorkerGroup>();
        }

        public LongId Id { get; set; }
        public DateTime? Created { get; set; }
        public DateTime? AgreedToTermsOn { get; set; }
        public NameLabel Name { get; set; }
        public GuidStr ApiKey { get; set; }
        public string CustomUrl { get; set; }

        public virtual ICollection<WorkerGroup> WorkerGroups { get; set; }
    }

Where LongId, NameLabel, GuidStr have C# primitive types of long, string, string respectively, with appropriate validation checks (e.g. under a certain length for NameLabel, and of certain format for GuidStr).

The code compiles fine, however when I actually try to fetch one of the above record from the database, I’m running into this error: System.InvalidOperationException: The property 'Account.Id' is of type 'LongId' which is not supported by the current database provider. Either change the property CLR type, or ignore the property using the '[NotMapped]' attribute or by using 'EntityTypeBuilder.Ignore' in 'OnModelCreating'.

I also tried to annotate the model with something like [Column(TypeName = "bigint")] on the Id property for example, and it didn’t do anything. So I just wanted to ask you if what I’m trying to do is reasonable and/or feasible. Maybe I should just return to using primitive C# types?

[jlauwers]

If you want a generic ValueOfConverter:

public class ValueOfConverter<T, TType> : ValueConverter<T, TType>
    where T : ValueOf<TType, T>, new()
{
    public ValueOfConverter() : base(
        id => id.Value,
        id => ValueOf<TType, T>.From(id))
    {
    }
}

builder.Property(x => x.Foobar).HasConversion<ValueOfConverter<Foobar, int>>();

[SteveDunn]

Vogen is similar to this but it has certain opinions/constraints on safety (for instance, not being able to create default instances of value objects). It’s also focused on speed; there’s almost no overheard compared to using a primitive directly. It’s a source generator, and can generate code for EF (as well as Json and Dapper). I’m not after stealing customers away from this very useful little package, but you might find it has what you need (if you’re happy with the constraints it imposes)