strongly typing IDs using implicit operator?

[jakobadam]

I was trying to replace an id long with a more informative type, using the following approach:

[TableName("Agreement")]
[PrimaryKey("Id")]
 public class Agreement
{
  public AgreementId Id { get; set;  } // a bigint in the db
       
   // ...
}

public class AgreementId
{
    private readonly long _value;

    public AgreementId(long value)
    {
        _value = value;
    }

    public static implicit operator long(AgreementId id) => id._value;

    public static implicit operator AgreementId(long value) => new AgreementId(value);
}

However, after that change the id property is not populated (is null)

db.Query<Agreement>().First() // id is null after change...

Is something like this possible?

By the way, the chat channel domain has been 'hijacked' by some bogus site.

kind regards,
Jakob