How can I make an EF Core entity ValueGenerated property value be used when querying using Linq query with .where(), instead of the database value?
For example, instead of directly translating from Linq to SQL with
(canApprove == true)
it should use:
((Approved == null && Configuration.MaxNumber > 1) == true)
Since is the value generator logic in the class
public class Event
{
public Configuration Configuration { get; set; }
public bool CanApprove
{
get => canApprove();
private set => _canApprove = value;
}
protected virtual bool canApprove() => Approved == null && Configuration.MaxNumber > 1;
}
builder.Property(e => e.CanApprove)
.HasValueGenerator<ValueGeneratorEventCanApprove >()
.UsePropertyAccessMode(PropertyAccessMode.Property);`
class ValueGeneratorEventCanApprove: Microsoft.EntityFrameworkCore.ValueGeneration.ValueGenerator
{
public override bool GeneratesTemporaryValues => false;
protected override object NextValue(EntityEntry entry) => ((Event)entry.Entity).CanApprove;
}
_context.Events.Where((e) => e.CanApprove == true) should be translated to SQL as:
((Approved == null && Configuration.MaxNumber > 1) == true)
instead of
(canApprove == true)
I can't find any solution different to try unless filter by using the background fields used in the logic of .canApprove.
var query = context.Events
.Where(e => e.Approved == null
&& e.Configuration.MaxNumber > 1)
.Select(e => new
{
Event = e,
CanApprove = e.Approved == null && e.Configuration.MaxNumber > 1
})
.Where(e => e.CanApprove)
.Select(e => e.Event);
or
_context.Events.Where((e) => e.Approved == true && e.Configuration.MaxNumber> 1)
Both approaches are not good for maintenance purposes since canApprove logic is quite complex, and used in many places.
I could also make use of future events to update the canApprove values, or a batch job to do that.
IQueryable<Event> CanApprove(this IQueryable<Event> query) => query.Where(... etc...);static Expression<Func<Event, bool>> CanApprove = e => e...etc...;then.Where(Event.CanApprove). Plenty of ways to reuse code and maintain it in a single place.