DataFilter.Core 1.1.1

DataFilter.Core

The foundation of the DataFilter library, providing pure filtering logic, abstractions, and standard data models.

NuGet integration

Install the package

dotnet add package DataFilter.Core

Target frameworks

net8.0, net9.0, netstandard2.0, netstandard2.1

Dependencies

None (UI-independent). Optional companion packages: DataFilter.Filtering.ExcelLike for Excel-style descriptors, DataFilter.Expressions.Server for LINQ translation.

Quick start

using DataFilter.Core.Abstractions;
using DataFilter.Core.Enums;
using DataFilter.Core.Models;
using DataFilter.Core.Pipeline;
using DataFilter.Core.Services;

// In-memory filtering
var context = new FilterContext();
context.AddOrUpdateDescriptor(new FilterDescriptor
{
    PropertyName = "Department",
    Operator = FilterOperator.Equals,
    Value = "IT"
});

var engine = new ReflectionFilterEngine();
var filtered = engine.Apply(employees, typeof(Employee), context.Descriptors);

// Filter pipeline preset (ordered criteria + multi-column sort)
var snapshot = new FilterPipelineSnapshot();
FilterPipelineSnapshotEditor.AddRootCriterion(snapshot, "IsActive", nameof(FilterOperator.Equals), true);
FilterPipelineSnapshotEditor.AddSort(snapshot, "Name", isDescending: false);

var pipeline = FilterPipelineSnapshotMapper.ToPipeline(snapshot);
context.ReplaceDescriptors(FilterPipelineCompiler.Compile(pipeline));

Structure

• Abstractions: IFilterEngine, IFilterDescriptor, IFilterContext, IAsyncDataProvider, etc.
• Engine: FilterExpressionBuilder, ReflectionFilterEngine, FilterEvaluator (wildcard text matching).
• Models: FilterSnapshot, FilterPipelineSnapshot, SortDescriptor, PagedResult.
• Pipeline (Pipeline/): FilterPipeline, CriterionPipelineNode, GroupPipelineNode — editable graph for UI scenarios (order, named groups, toggles).
• Services: FilterSnapshotBuilder, FilterPipelineCompiler, FilterPipelineSnapshotMapper, FilterPipelineSnapshotEditor, FilterPipelineInterop, FilterPipelineContextExtensions.

Key Concepts

Wildcards in text operators (*, ?)

Core text operators (Equals, NotEquals, Contains, NotContains, StartsWith, EndsWith) support wildcard patterns:

• * matches any sequence of characters
• ? matches a single character

This behavior is implemented in FilterEvaluator and FilterExpressionBuilder, so it applies consistently to in-memory filtering and compiled expressions. Persisted presets that store a text operator + pattern replay correctly without UI-specific logic.

FilterSnapshot

A serializable representation of a filtering state that can be passed between layers (e.g., from Blazor UI to Web API). Describes what is filtered using flat or nested FilterSnapshotEntry rows (including logical groups for Excel-style column scopes).

Filter pipeline

For applications that need an ordered list of criteria, named groups, enable/disable flags, and JSON presets, use the pipeline model:

Apply to runtime state with FilterContext.ReplaceDescriptors(FilterPipelineCompiler.Compile(pipeline)) or FilterPipelineContextExtensions.ApplyToContext(pipeline, filterContext). This replaces the entire descriptor list; it does not merge by property name (unlike AddOrUpdateDescriptor).

// Edit snapshot in memory, then compile and apply
var snapshot = FilterPipelineSnapshotEditor.Clone(existing);
FilterPipelineSnapshotEditor.AddRootCriterion(snapshot, "Name", nameof(FilterOperator.StartsWith), "A");
var pipeline = FilterPipelineSnapshotMapper.ToPipeline(snapshot);
context.ReplaceDescriptors(FilterPipelineCompiler.Compile(pipeline));

IAsyncDataProvider

Implement this interface to provide data asynchronously from any source (SQL, NoSQL, API).

public interface IAsyncDataProvider<T>
{
    Task<PagedResult<T>> FetchDataAsync(IFilterContext context, CancellationToken cancellationToken = default);
    Task<IEnumerable<object>> FetchDistinctValuesAsync(string propertyName, string searchText = "", CancellationToken cancellationToken = default);
}