Filtering enums¶

What this does¶

When a [Map] targets a property typed as a C# enum, the source generator scans the entity's property graph (via EnumTypeCollector) and auto-emits a profile named Filtering.Net.Generated.<EnumName>Filter. You do not write a [FilterProfile<TEnum>] declaration by hand — the generator produces it for every reachable enum and wires it to the matching [Map]. The default operator catalogue for an enum is eq, ne, in, isNull.

When to use¶

Every [Map] whose target property is a C# enum. This is the zero-boilerplate path: declare the enum, declare the property, declare the [Map], and filtering just works.

Minimal code¶

Lifted from samples/UserManagement.WebApi/Models/User.cs and Filters/UserFilter.cs:

public enum UserStatus
{
    Active,
    Pending,
    Suspended,
    Banned,
}

public sealed class User
{
    public int Id { get; set; }
    public UserStatus Status { get; set; }
    // ... other properties
}

[GenerateFilter<User>]
public partial class UserFilter
{
    // No Profile = typeof(...) — the generator auto-emits Filtering.Net.Generated.UserStatusFilter
    // and wires it to this property automatically.
    [Map(nameof(User.Status), Sortable = true)]
    private static partial void MapStatus();
}

A request leaf:

{ "field": "Status", "op": "in", "value": ["Active", "Pending"] }

Variations¶

Query by enum name (string) — the JSON value parses by name: "value": "Active".
Query by numeric value (int) — the JSON value parses by ordinal: "value": 0 (where Active = 0).
in with mixed shapes — every element of an in array is parsed independently, so ["Active", 1, "Banned"] is well-formed.
isNull on a nullable enum — when the property is UserStatus?, the auto-emitted profile carries isNull semantics that match the column's nullability.

Pitfalls¶

When the column is stored as a string in the database, register an EF Core ValueConverter<TEnum, string> on the model side via modelBuilder.Entity<T>().Property(x => x.Status).HasConversion<MyEnumStringConverter>() in OnModelCreating. EF then translates the generated predicate against the model-side enum into the right SQL (WHERE status = 'Active') — Filtering.Net stays out of that pipeline.
An invalid enum name in the JSON value ("value": "Bogus") fails validation with InvalidValueFormat — the deserializer rejects it before predicate building.
Adding a [FilterProfile<UserStatus>] of your own collides with the auto-emitted one; remove the auto-emission path by selecting your custom profile via [Map(..., Profile = typeof(MyUserStatusFilter))] on every relevant [Map].