v4.0 Changes

Removed NonGenericEnums, NonGenericFlagEnums, UnsafeEnums, and UnsafeFlagEnums classes which were deprecated in v3.0 and also removed all other deprecated methods in an effort to slim the library size down. It is recommended if upgrading from 2.x and below to update to 3.x first and follow the warnings to migrate any code that's using deprecated methods and classes. Also, a dependency on the System.Runtime.CompilerServices.Unsafe package was added for the .NET 4.5 target in order to remove a build dependency on Fody.

v3.0 Changes

One of the major changes for v3.0 is the deprecation of the NonGenericEnums, NonGenericFlagEnums, UnsafeEnums, and UnsafeFlagEnums classes whose methods have been added to the Enums and FlagEnums classes to better match System.Enum and provide better discoverability. To help you migrate your code to using the new methods I have created the C# roslyn analyzer Enums.NET.Analyzer which provides a code fix to migrate your usages of the non-generic and unsafe methods to the new methods.

Enums.NET

Enums.NET is a high-performance type-safe .NET enum utility library which provides many operations as convenient extension methods. It is compatible with .NET Framework 4.5+ and .NET Standard 1.0+.

What's wrong with System.Enum

1. Nearly all of Enum's static methods are non-generic leading to the following issues.
   • Requires the enum type to be explicitly specified as an argument and requires invocation using static method syntax such as Enum.IsDefined(typeof(ConsoleColor), value) instead of what should be value.IsDefined().
   • Requires casting/unboxing for methods with an enum return value, eg. ToObject, Parse, and GetValues.
   • Requires boxing for methods with enum input parameters losing type-safety, eg. IsDefined and GetName.
2. Support for flag enums is limited to just the HasFlag method which isn't type-safe, is inefficient, and is ambiguous as to whether it determines if the value has all or any of the specified flags. It's all by the way.
3. Most of its methods use reflection on each call without any sort of caching causing poor performance.
4. The pattern to associate extra data with an enum member using Attributes is not supported and instead requires users to manually retrieve the Attributes via reflection. This pattern is commonly used on enum members with the DescriptionAttribute, EnumMemberAttribute, and DisplayAttribute.

Enums.NET solves all of these issues and more.

Enums.NET Demo

using System;
using System.Linq;
using EnumsNET;
using NUnit.Framework;
using DescriptionAttribute = System.ComponentModel.DescriptionAttribute;

[TestFixture]
class EnumsNETDemo
{
    // Enum definitions at bottom

    [Test]
    public void Enumerate()
    {
        var count = 0;
        // Retrieves all enum members in increasing value order
        foreach (var member in Enums.GetMembers<NumericOperator>())
        {
            NumericOperator value = member.Value;
            string name = member.Name;
            AttributeCollection attributes = member.Attributes;
            ++count;
        }
        Assert.AreEqual(8, count);

        count = 0;
        // Retrieves distinct values in increasing value order
        foreach (var value in Enums.GetValues<NumericOperator>(EnumMemberSelection.Distinct))
        {
            string name = value.GetName();
            AttributeCollection attributes = value.GetAttributes();
            ++count;
        }
        Assert.AreEqual(6, count);
    }

    [Test]
    public void FlagEnumOperations()
    {
        // HasAllFlags
        Assert.IsTrue((DaysOfWeek.Monday | DaysOfWeek.Wednesday | DaysOfWeek.Friday).HasAllFlags(DaysOfWeek.Monday | DaysOfWeek.Wednesday));
        Assert.IsFalse(DaysOfWeek.Monday.HasAllFlags(DaysOfWeek.Monday | DaysOfWeek.Wednesday));

        // HasAnyFlags
        Assert.IsTrue(DaysOfWeek.Monday.HasAnyFlags(DaysOfWeek.Monday | DaysOfWeek.Wednesday));
        Assert.IsFalse((DaysOfWeek.Monday | DaysOfWeek.Wednesday).HasAnyFlags(DaysOfWeek.Friday));

        // CombineFlags ~ bitwise OR
        Assert.AreEqual(DaysOfWeek.Monday | DaysOfWeek.Wednesday, DaysOfWeek.Monday.CombineFlags(DaysOfWeek.Wednesday));
        Assert.AreEqual(DaysOfWeek.Monday | DaysOfWeek.Wednesday | DaysOfWeek.Friday, FlagEnums.CombineFlags(DaysOfWeek.Monday, DaysOfWeek.Wednesday, DaysOfWeek.Friday));

        // CommonFlags ~ bitwise AND
        Assert.AreEqual(DaysOfWeek.Monday, DaysOfWeek.Monday.CommonFlags(DaysOfWeek.Monday | DaysOfWeek.Wednesday));
        Assert.AreEqual(DaysOfWeek.None, DaysOfWeek.Monday.CommonFlags(DaysOfWeek.Wednesday));

        // RemoveFlags
        Assert.AreEqual(DaysOfWeek.Wednesday, (DaysOfWeek.Monday | DaysOfWeek.Wednesday).RemoveFlags(DaysOfWeek.Monday));
        Assert.AreEqual(DaysOfWeek.None, (DaysOfWeek.Monday | DaysOfWeek.Wednesday).RemoveFlags(DaysOfWeek.Monday | DaysOfWeek.Wednesday));

        // GetFlags, splits out the individual flags in increasing significance bit order
        var flags = DaysOfWeek.Weekend.GetFlags();
        Assert.AreEqual(2, flags.Count);
        Assert.AreEqual(DaysOfWeek.Sunday, flags[0]);
        Assert.AreEqual(DaysOfWeek.Saturday, flags[1]);
    }

    [Test]
    public new void ToString()
    {
        // AsString, equivalent to ToString
        Assert.AreEqual("Equals", NumericOperator.Equals.AsString());
        Assert.AreEqual("-1", ((NumericOperator)(-1)).AsString());

        // GetName
        Assert.AreEqual("Equals", NumericOperator.Equals.GetName());
        Assert.IsNull(((NumericOperator)(-1)).GetName());

        // Get description
        Assert.AreEqual("Is", NumericOperator.Equals.AsString(EnumFormat.Description));
        Assert.IsNull(NumericOperator.LessThan.AsString(EnumFormat.Description));

        // Get description if applied, otherwise the name
        Assert.AreEqual("LessThan", NumericOperator.LessThan.AsString(EnumFormat.Description, EnumFormat.Name));
    }

    [Test]
    public void Validate()
    {
        // Standard Enums, checks is defined
        Assert.IsTrue(NumericOperator.LessThan.IsValid());
        Assert.IsFalse(((NumericOperator)20).IsValid());

        // Flag Enums, checks is valid flag combination or is defined
        Assert.IsTrue((DaysOfWeek.Sunday | DaysOfWeek.Wednesday).IsValid());
        Assert.IsFalse((DaysOfWeek.Sunday | DaysOfWeek.Wednesday | ((DaysOfWeek)(-1))).IsValid());

        // Custom validation through IEnumValidatorAttribute<TEnum>
        Assert.IsTrue(DayType.Weekday.IsValid());
        Assert.IsTrue((DayType.Weekday | DayType.Holiday).IsValid());
        Assert.IsFalse((DayType.Weekday | DayType.Weekend).IsValid());
    }

    [Test]
    public void CustomEnumFormat()
    {
        EnumFormat symbolFormat = Enums.RegisterCustomEnumFormat(member => member.Attributes.Get<SymbolAttribute>()?.Symbol);
        Assert.AreEqual(">", NumericOperator.GreaterThan.AsString(symbolFormat));
        Assert.AreEqual(NumericOperator.LessThan, Enums.Parse<NumericOperator>("<", ignoreCase: false, symbolFormat));
    }

    [Test]
    public void Attributes()
    {
        Assert.AreEqual("!=", NumericOperator.NotEquals.GetAttributes().Get<SymbolAttribute>().Symbol);
        Assert.IsTrue(Enums.GetMember<NumericOperator>("GreaterThanOrEquals").Attributes.Has<PrimaryEnumMemberAttribute>());
        Assert.IsFalse(NumericOperator.LessThan.GetAttributes().Has<DescriptionAttribute>());
    }

    [Test]
    public void Parsing()
    {
        Assert.AreEqual(NumericOperator.GreaterThan, Enums.Parse<NumericOperator>("GreaterThan"));
        Assert.AreEqual(NumericOperator.NotEquals, Enums.Parse<NumericOperator>("1"));
        Assert.AreEqual(NumericOperator.Equals, Enums.Parse<NumericOperator>("Is", ignoreCase: false, EnumFormat.Description));

        Assert.AreEqual(DaysOfWeek.Monday | DaysOfWeek.Wednesday, Enums.Parse<DaysOfWeek>("Monday, Wednesday"));
        Assert.AreEqual(DaysOfWeek.Tuesday | DaysOfWeek.Thursday, FlagEnums.ParseFlags<DaysOfWeek>("Tuesday | Thursday", ignoreCase: false, delimiter: "|"));
    }

    enum NumericOperator
    {
        [Symbol("="), Description("Is")]
        Equals,
        [Symbol("!="), Description("Is not")]
        NotEquals,
        [Symbol("<")]
        LessThan,
        [Symbol(">="), PrimaryEnumMember] // PrimaryEnumMember indicates enum member as primary duplicate for extension methods
        GreaterThanOrEquals,
        NotLessThan = GreaterThanOrEquals,
        [Symbol(">")]
        GreaterThan,
        [Symbol("<="), PrimaryEnumMember]
        LessThanOrEquals,
        NotGreaterThan = LessThanOrEquals
    }

    [AttributeUsage(AttributeTargets.Field)]
    class SymbolAttribute : Attribute
    {
        public string Symbol { get; }

        public SymbolAttribute(string symbol)
        {
            Symbol = symbol;
        }
    }

    [Flags]
    enum DaysOfWeek
    {
        None = 0,
        Sunday = 1,
        Monday = 2,
        Tuesday = 4,
        Wednesday = 8,
        Thursday = 16,
        Friday = 32,
        Weekdays = Monday | Tuesday | Wednesday | Thursday | Friday,
        Saturday = 64,
        Weekend = Sunday | Saturday,
        All = Sunday | Monday | Tuesday | Wednesday | Thursday | Friday | Saturday
    }

    [Flags, DayTypeValidator]
    enum DayType
    {
        Weekday = 1,
        Weekend = 2,
        Holiday = 4
    }

    [AttributeUsage(AttributeTargets.Enum)]
    class DayTypeValidatorAttribute : Attribute, IEnumValidatorAttribute<DayType>
    {
        public bool IsValid(DayType value) => value.GetFlagCount(DayType.Weekday | DayType.Weekend) == 1 && FlagEnums.IsValidFlagCombination(value);
    }
}

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Results from running the PerformanceTestConsole BenchmarkDotNet application.

Interface

See fuget for exploring the interface.

Credits

Inspired by Jon Skeet's Unconstrained Melody.