ILLightenComparer 1.2.1

dotnet add package ILLightenComparer --version 1.2.1
NuGet\Install-Package ILLightenComparer -Version 1.2.1
This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package.
<PackageReference Include="ILLightenComparer" Version="1.2.1" />
For projects that support PackageReference, copy this XML node into the project file to reference the package.
paket add ILLightenComparer --version 1.2.1
#r "nuget: ILLightenComparer, 1.2.1"
#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package.
// Install ILLightenComparer as a Cake Addin
#addin nuget:?package=ILLightenComparer&version=1.2.1

// Install ILLightenComparer as a Cake Tool
#tool nuget:?package=ILLightenComparer&version=1.2.1

Fast comparer library

Build status codecov NuGet Badge

ILLightenComparer is a flexible library that can generate very effective and comprehensive IComparer<T> and IEqualityComparer<T> implementations on runtime using advantages of IL code emission.


  • Support for classes and structures any complexity and nesting.
  • Highly configurable.
  • Fluent intuitive API.
  • Cycle detection.
  • Collections comparison (IEnumerable<T>, T[], T[][]).
  • .NET Standard 2.0, .NET 5.
  • High performance.
  • No 3<sup>rd</sup> party dependencies.

Configuration options

  • Cycle detection.
  • Ignoring collections order.
  • Ignoring members.
  • Including fields into comparison.
  • Defining order in which members will be compared.
  • Defining string comparison type.
  • Defining custom comparers by type or instance.


Basic usage

var comparer = ComparerBuilder.Default.GetComparer<Tuple<int, string>>();
var compareResult = comparer.Compare(x, y);

var equalityComparer = ComparerBuilder.Default.GetEqualityComparer<Tuple<int, string>>();
var equalityResult = equalityComparer.Equals(x, y);
var hashResult = equalityComparer.GetHashCode(x);

And it "just works", no need complex configuration.

Ignore collection order

var x = new[] { 1, 2, 3 };
var y = new[] { 2, 3, 1 };

var comparer = new ComparerBuilder()
    .For<int[]>(c => c.IgnoreCollectionsOrder(true))

var result = comparer.Compare(x, y);

Ignore specific members

var x = new Tuple<int, string, double>(1, "value 1", 1.1);
var y = new Tuple<int, string, double>(1, "value 2", 2.2);

var comparer = new ComparerBuilder()
    .For<Tuple<int, string, double>>()
    .Configure(c => c.IgnoreMember(o => o.Item2)
                     .IgnoreMember(o => o.Item3))

var result = comparer.Compare(x, y);

Define custom comparer

var x = _fixture.Create<Tuple<int, string>>();
var y = _fixture.Create<Tuple<int, string>>();
var customComparer = new CustomizableComparer<Tuple<int, string>>((a, b) => 0); // makes all objects always equal

var comparer = new ComparerBuilder()
    .Configure(c => c.SetCustomComparer(customComparer))
    .GetComparer<Tuple<int, string>>();

var result = comparer.Compare(x, y);

Define multiple configurations

var builder = new ComparerBuilder(c => c.SetDefaultCyclesDetection(false)); // defines initial configuration

// adds some configuration later
builder.Configure(c => c
        typeof(Tuple<int, string, Tuple<short, string>>),
    .IgnoreMember<Tuple<int, string, Tuple<short, string>>, int>(o => o.Item1));

// defines configuration for specific types
builder.For<Tuple<short, string>>(c => c.DefineMembersOrder(
    order => order.Member(o => o.Item2)
                  .Member(o => o.Item2)));

// adds additional configuration to existing configuration
builder.For<Tuple<int, string, Tuple<short, string>>>(c => c.IncludeFields(false));


  • Configuration is fixed for generated comparer. If you want to change configuration you have to request new comparer:
    var x = new Tuple<int, string>(1, "text");
    var y = new Tuple<int, string>(2, "TEXT");
    // initially configuration defines case insensitive string comparison
    var builder = new ComparerBuilder()
        .For<Tuple<int, string>>(c => c
    // in addition, setup to ignore first member
    builder.Configure(c => c.IgnoreMember(o => o.Item1));
    // this version takes in account only case insensitive second member
    var ignoreCaseComparer = builder.GetComparer();
    // override string comparison type with case sensitive setting and build new comparer
    var originalCaseComparer = builder
        .For<Tuple<int, string>>()
        .Configure(c => c.SetStringComparisonType(StringComparison.Ordinal))
    // first comparer ignores case for strings still
    ignoreCaseComparer.Compare(x, y).Should().Be(0);
    // second comparer still ignores first member but uses new string comparison type
    var result = originalCaseComparer.Compare(x, y);
    result.Should().Be(string.Compare("text", "TEXT", StringComparison.Ordinal));
  • To help generate more effective code use sealed classes and small types (sbyte, byte, char, short, ushort) when possible.
  • For safety reasons cycle detection is enabled by default. But when you are sure that it is not possible you can disable it and get significant performance boost.
  • protected and private members are ignored during comparison.
  • Multidimensional arrays are not supported now, but Jagged arrays are.
  • If a type implements IComparable<T> interface then this implementations will be used.
  • Benchmarks

In case of an unexpected behavior, please welcome to create an issue and provide the type and data that you use.

Product Compatible and additional computed target framework versions.
.NET net5.0 is compatible.  net5.0-windows was computed.  net6.0 was computed.  net6.0-android was computed.  net6.0-ios was computed.  net6.0-maccatalyst was computed.  net6.0-macos was computed.  net6.0-tvos was computed.  net6.0-windows was computed.  net7.0 was computed.  net7.0-android was computed.  net7.0-ios was computed.  net7.0-maccatalyst was computed.  net7.0-macos was computed.  net7.0-tvos was computed.  net7.0-windows was computed.  net8.0 was computed.  net8.0-android was computed.  net8.0-browser was computed.  net8.0-ios was computed.  net8.0-maccatalyst was computed.  net8.0-macos was computed.  net8.0-tvos was computed.  net8.0-windows was computed. 
.NET Core netcoreapp2.0 was computed.  netcoreapp2.1 was computed.  netcoreapp2.2 was computed.  netcoreapp3.0 was computed.  netcoreapp3.1 was computed. 
.NET Standard netstandard2.0 is compatible.  netstandard2.1 was computed. 
.NET Framework net461 was computed.  net462 was computed.  net463 was computed.  net47 was computed.  net471 was computed.  net472 was computed.  net48 was computed.  net481 was computed. 
MonoAndroid monoandroid was computed. 
MonoMac monomac was computed. 
MonoTouch monotouch was computed. 
Tizen tizen40 was computed.  tizen60 was computed. 
Xamarin.iOS xamarinios was computed. 
Xamarin.Mac xamarinmac was computed. 
Xamarin.TVOS xamarintvos was computed. 
Xamarin.WatchOS xamarinwatchos was computed. 
Compatible target framework(s)
Included target framework(s) (in package)
Learn more about Target Frameworks and .NET Standard.

NuGet packages

This package is not used by any NuGet packages.

GitHub repositories

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Version Downloads Last updated
1.2.1 338 4/11/2021
1.1.0 283 4/4/2021
1.0.0 437 5/17/2020
0.3.1 403 5/5/2020
0.2.0 540 3/31/2019