Equatable.Generator

Source generator for Equals and GetHashCode with attribute based control of equality implementation

Features

• Override Equals and GetHashCode
• Implement IEquatable<T>
• Support class, record and struct types
• Support EqualityComparer per property via attribute
• Attribute based control of equality implementation.
• Attribute comparers supported: String, Sequence, Dictionary, HashSet, Reference, and Custom
• No runtime dependencies. Library is compile time dependence only.

Usage

Add package

Add the nuget package to your projects.

dotnet add package Equatable.Generator

Prevent including Equatable.Generator as a dependency

<PackageReference Include="Equatable.Generator" PrivateAssets="all" />

Requirements

This library requires:

• Target framework .NET Standard 2.0 or greater
• Project C# LangVersion 8.0 or higher

Equatable Attributes

Place [Equatable] attribute on a class, record or struct. The source generator will create a partial with overrides for Equals and GetHashCode for all public properties.

• [Equatable] Marks the class to generate overrides for Equals and GetHashCode

The default comparer used in the implementation of Equals and GetHashCode is EqualityComparer<T>.Default. Customize the comparer used with the following attributes.

• [IgnoreEquality] Ignore property in Equals and GetHashCode implementations
• [StringEquality] Use specified StringComparer when comparing strings
• [SequenceEquality] Use Enumerable.SequenceEqual to determine whether enumerables are equal
• [DictionaryEquality] Use to determine if dictionaries are equal
• [HashSetEquality] Use ISet<T>.SetEquals to determine whether enumerables are equal
• [ReferenceEquality] Use Object.ReferenceEquals to determines whether instances are the same instance
• [EqualityComparer] Use the specified EqualityComparer

Example Usage

Example of using the attributes to customize the source generation of Equals and GetHashCode

[Equatable]
public partial class UserImport
{
    [StringEquality(StringComparison.OrdinalIgnoreCase)]
    public string EmailAddress { get; set; } = null!;

    public string? DisplayName { get; set; }

    public string? FirstName { get; set; }

    public string? LastName { get; set; }

    public DateTimeOffset? LockoutEnd { get; set; }

    public DateTimeOffset? LastLogin { get; set; }

    [IgnoreEquality]
    public string FullName => $"{FirstName} {LastName}";

    [HashSetEquality]
    public HashSet<string>? Roles { get; set; }

    [DictionaryEquality]
    public Dictionary<string, int>? Permissions { get; set; }

    [SequenceEquality]
    public List<DateTimeOffset>? History { get; set; }
}

Works for record types too

[Equatable]
public partial record StatusRecord(
    int Id,
    [property: StringEquality(StringComparison.OrdinalIgnoreCase)] string Name,
    string? Description,
    int DisplayOrder,
    bool IsActive,
    [property: SequenceEquality] List<string> Versions
);