Custom sorting logic on specific fields

[stephanejbx]

Hey,

Is there a way to define a custom sorting logic for a field, while keep the implicit logic for all the other props?

My use case is:

I have a class with

public class Foo
{
    public double A { get; set; }
    public string B { get; set; }
}

I already have a custom type like so

public class CustomFooType : ObjectType<Foo>
    {
        protected override void Configure(IObjectTypeDescriptor<Foo> descriptor)
        {
            descriptor.Field(d => d.A).Ignore();
            descriptor.Field(d => d.B)
                .Type<StringType>()
                .Resolve(context => context.Parent<Foo>().A.ToString($"weird things that don't order properly"));
        }
    }

The query result looks great and does what I want, however, what I want would be to sort on A when querying the sorting on B.

Ideas welcomed! Thanks

[stephanejbx]

I ended up - I think - achieving it like this, based on this discussion

public class FooSortConvention : SortConvention
{
    protected override void Configure(ISortConventionDescriptor descriptor)
    {
        descriptor.AddDefaults();
        descriptor
            .AddProviderExtension(
                new QueryableSortProviderExtension(_ => _
                    .AddFieldHandler(new FooBSortHandler())));
    }
}

public class FooBSortHandler : QueryableDefaultSortFieldHandler
{
    public override bool TryHandleEnter(QueryableSortContext context, ISortField field, ObjectFieldNode node, [NotNullWhen(true)] out ISyntaxVisitorAction action)
    {
        if (field.Name == "B")
        {
            Expression<Func<Estimate, double>> expression = e => e.A;
            var lastFieldSelector = (QueryableFieldSelector)context.GetInstance();
            var nextSelector = Expression.Invoke(expression, lastFieldSelector.Selector);
            context.PushInstance(lastFieldSelector.WithSelector(nextSelector));
            action = SyntaxVisitor.Continue;
            return true;
        }
        return base.TryHandleEnter(context, field, node, out action);
    }
}

I'm not sure it's all correct actually, wouldn't mind some feedback.

I also would really like to know if someone had this kind of issue sorted by applying a rule on a single property instead of having to register a convention on the whole API.