JOS.Enumeration

Enumeration implementation with source generation support.

Installation

JOS.Enumeration

Contains the IEnumeration interface and a System.Text.Json JsonConverter. The JOS.Enumeration.SourceGenerator package contains the actual source generator.

Don't forget to install that one as well. 😃

dotnet add package JOS.Enumeration
dotnet add package JOS.Enumeration.SourceGenerator

JOS.Enumeration.Database.Dapper

Contains a custom TypeHandler to use with Dapper.

dotnet add package JOS.Enumeration.Database.Dapper

JOS.Enumeration.Database.EntityFrameworkCore

Contains ConfigureEnumeration extension method to allow usage with EntityFramework Core.

dotnet add package JOS.Enumeration.Database.EntityFrameworkCore

Usage

• Create a new partial record or class
• Implement the IEnumeration<T> interface
• Add your Enumeration items

public partial record Hamburger : IEnumeration<Hamburger>
{
    public static readonly Hamburger Cheeseburger = new (1, "Cheeseburger");
    public static readonly Hamburger BigMac = new(2, "Big Mac");
    public static readonly Hamburger BigTasty = new(3, "Big Tasty");
}

The source generator will implement the following interface:

// Default implementation -> int as Value
public interface IEnumeration<T> : IEnumeration<int, T> where T : IEnumeration<T>
{
}

public interface IEnumeration<TValue, TType> where TValue : IConvertible
{
    TValue Value { get; }
    string Description { get; }
    static abstract IReadOnlySet<TType> GetAll();
    static abstract IEnumerable<TType> GetEnumerable();
    static abstract TType FromValue(TValue value);
    static abstract TType FromDescription(string description);
    static abstract TType FromDescription(ReadOnlySpan<char> description);
    static abstract Type ValueType { get; }
}

The following code will be generated:

[System.Diagnostics.DebuggerDisplay("{Description}")]
public partial record Hamburger : IComparable<JOS.Enumerations.Hamburger>
{
    private static readonly IReadOnlySet<JOS.Enumerations.Hamburger> AllItems;
    
    static Hamburger()
    {
        AllItems = new HashSet<JOS.Enumerations.Hamburger>(3)
        {
            Cheeseburger,
            BigMac,
            BigTasty
        }.ToFrozenSet(optimizeForReading: true);
    }

    private Hamburger(int value, string description)
    {
        Value = value;
        Description = description ?? throw new ArgumentNullException(nameof(description));
    }

    public int Value { get; }

    public string Description { get; }

    public static IReadOnlySet<JOS.Enumerations.Hamburger> GetAll()
    {
        return AllItems;
    }

    public static IEnumerable<JOS.Enumerations.Hamburger> GetEnumerable()
    {
        yield return Cheeseburger;
        yield return BigMac;
        yield return BigTasty;
    }

    public static JOS.Enumerations.Hamburger FromValue(int value)
    {
        return value switch
        {
            1 => Cheeseburger,
            2 => BigMac,
            3 => BigTasty,
            _ => throw new InvalidOperationException($"'{value}' is not a valid value in 'JOS.Enumerations.Hamburger'")
        };
    }

    public static JOS.Enumerations.Hamburger FromDescription(string description)
    {
        return description switch
        {
            "Cheeseburger" => Cheeseburger,
            "Big Mac" => BigMac,
            "Big Tasty" => BigTasty,
            _ => throw new InvalidOperationException($"'{description}' is not a valid description in 'JOS.Enumerations.Hamburger'")
        };
    }

    public static JOS.Enumerations.Hamburger FromDescription(ReadOnlySpan<char> description)
    {
        return description switch
        {
            "Cheeseburger" => Cheeseburger,
            "Big Mac" => BigMac,
            "Big Tasty" => BigTasty,
            _ => throw new InvalidOperationException($"'{description}' is not a valid description in 'JOS.Enumerations.Hamburger'")
        };
    }

    public static Type ValueType => typeof(int);
    public int CompareTo(JOS.Enumerations.Hamburger? other) => Value.CompareTo(other!.Value);
    public static implicit operator int (JOS.Enumerations.Hamburger item) => item.Value;
    public static implicit operator JOS.Enumerations.Hamburger(int value) => FromValue(value);
}

Features

• Generic value
• Generated IComparable<T> method.
• Generated implicit operators (convert to/from int).
• Generated optimized GetAll, FromValue and FromDescription methods.
• System.Text.Json support
• Database support (Dapper and EF Core).

Generic value

It's possible to use a generic value instead of the default int value by implementing the IEnumeration<TValue, TEnumeration> interface.

public partial record Car : IEnumeration<string, Car>
{
    public static readonly Car FerrariSpider = new("ferrari-spider", "Ferrari Spider");
    public static readonly Car TeslaModelY = new("tesla-model-y", "Tesla Model Y");
}

TValue has a IConvertible constraint.

The following types has been tested and are guaranteed to work:

• int (default)
• bool
• decimal
• long
• string
• uint
• ulong

JSON

The package comes with a generic JsonConverter. You'll need to register a custom converter for each enumeration. Example:

var jsonSerializerOptions = new JsonSerializerOptions
{
    Converters = { new EnumerationJsonConverter<Hamburger>() }
};

If you're using a custom value, you need to register the converter like this:

var jsonSerializerOptions = new JsonSerializerOptions
{
    Converters = { new EnumerationJsonConverter<string, Car>() }
};

It supports the following scenarios:

• Serializing to TValue
• Deserializing from TValue

If you want any other behaviour, just create your own converter and register it.

Database

public class MyEntity
{
    public MyEntity(Guid id, Hamburger hamburger)
    {
        Id = id;
        Hamburger = hamburger;
    }

    public Guid Id { get; }
    public Hamburger Hamburger { get; }
}

Dapper

• Register the TypeHandler: SqlMapper.AddTypeHandler(new EnumerationTypeHandler<Hamburger>())
• Query like this:

var results = (await actConnection.QueryAsync<MyEntity>(
            "SELECT id, hamburger from my_entities WHERE id = @id", new {id = myEntity.Id})).ToList(); 

EF Core

• Configure your DB Context

public DbSet<MyEntity> MyEntities { get; set; } = null!;

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.ApplyConfigurationsFromAssembly(typeof(JosEnumerationDbContext).Assembly);
} 

public class MyEntityEntityTypeConfiguration : IEntityTypeConfiguration<MyEntity>
{
    public void Configure(EntityTypeBuilder<MyEntity> builder)
    {
        builder.HasKey(x => x.Id);
        builder.Property(x => x.Hamburger).ConfigureEnumeration().IsRequired();
    }
}

• Query:

var result = await myDbContext.MyEntities.FirstAsync(x => x.Id == myEntity.Id); 

Primitive Collections

Support for primitive collections in net8.0 can be configured like this:

EF Core

public void Configure(EntityTypeBuilder<MyEntity> builder)
{
    builder.ConfigureEnumeration<MyEntity, string, Car>(x => x.Cars);
}

Dapper

SqlMapper.AddTypeHandler(new EnumerationArrayTypeHandler<string, Car>());