BlogDoFT.Libs.EntityFramework.CodeGenerator.Abstractions 10.1.0

BlogDoFT.Libs.EntityFramework.CodeGenerator.Abstractions

Strongly-typed attributes and enums used by the Predicate Generator.

These annotations are applied to filter DTOs so a source generator can emit ToPredicate() and HasFilter() methods.

Target Frameworks: netstandard2.0
C# Language Version: C# 11+ (required for generic attributes)

Contents

• GeneratePredicateAttribute<TEntity>
• StringFilterAttribute
• NumericFilterAttribute
• TemporalFilterAttribute
• BooleanFilterAttribute
• ComparisonOperator enum

Installation

Install it in the app project:

dotnet add package BlogDoFT.Libs.EntityFramework.CodeGenerator.Abstractions

Usage

Annotate your filter DTO with [GeneratePredicate<TEntity>] and mark each filterable property with the respective attribute.

using BlogDoFT.Libs.EntityFramework.CodeGenerator.Abstractions;

[GeneratePredicate<Domain.UserRecord>]
public partial class UserFilterDto
{
    [StringFilter(TargetProperty = nameof(Domain.UserRecord.Name), Order = 1)]
    public string? Name { get; init; }

    [StringFilter(TargetProperty = nameof(Domain.UserRecord.Email), Order = 2)]
    public string? Email { get; init; }

    [NumericFilter(TargetProperty = nameof(Domain.UserRecord.Age),
                   Operator = ComparisonOperator.GreaterThanOrEqual, Order = 3)]
    public int? MinimumAge { get; init; }

    [TemporalFilter(TargetProperty = nameof(Domain.UserRecord.CreatedAt),
                    Operator = ComparisonOperator.LessThanOrEqual, Order = 4)]
    public DateTime? CreatedUntil { get; init; }

    [BooleanFilter(TargetProperty = nameof(Domain.UserRecord.Active), Order = 5)]
    public bool? Active { get; init; }
}

The DTO must be partial. The generator adds the methods into the same type.

Behavior

Generated methods

Generated methods

• Expression<Func<TEntity, bool>> ToPredicate()
• bool HasFilter()

HasFilter() returns true if at least one annotated property holds a non-null value. ToPredicate() returns entity => true when all annotated values are null; otherwise it combines only the provided filters with logical AND.

String wildcards

When the string value contains %, the pattern is passed to the database (LIKE):

• No % → equality (field == value)
• Ends with % → database pattern (e.g., value%)
• Starts with % → database pattern (e.g., %value)
• % in the middle or both sides → database pattern (e.g., %val%ue%)

This relies on the generator’s provider-aware output (see the Generator README).

Numeric and temporal operators

NumericFilterAttribute and TemporalFilterAttribute accept Operator: ComparisonOperator:

• Equal, GreaterThan, LessThan, GreaterThanOrEqual, LessThanOrEqual.

Boolean properties

Always compared by equality.

Query Order

Usually, the where field orders matters - for database index usage.

Filters are composed by Order (if specified). Otherwise, DTO declaration order is used.

Requirements

C# 11+ (for generic attributes)

Works with EF Core 6/7/8+ (generator handles provider-specific differences)

Versioning

Starting with v10.0.0, this library's version numbering follows the major version of the .NET runtime it targets. For example, this version is compatible with .NET 10, so the major version is 10 — this explains the jump from the previous 1.x version series.