EntityFrameworkTraits 0.0.1

Entity Framework Traits

Compose your entity with set of traits / features / behaviours without inheritance

Purpose

The purpose of this library is to provide a way to compose your entity with set of traits / features / behaviours without inheritance. This is done by using interfaces and extension methods. This allows you to create a clean and maintainable codebase, while still being able to add new features to your entities easily.

According to https://en.wikipedia.org/wiki/Trait_(computer_programming): In computer programming, a trait is a language concept that represents a set of methods that can be used to extend the functionality of a class.

While traits are not a new concept, they are partially implemented in C# using interfaces and extension methods. This implementation have limitations of not providing the ability to extend the class with trait`s properties which are essential to entity definition in Entity Framework.

This library aims to provide a way to compose your entity with set of traits / features / behaviours without inheritance. This is done by using interfaces and code generation. This allows you to create a clean and maintainable codebase, while still being able to add new features to your entities easily.

Example

Step 1. Define your trait

public interface ISoftDeletable
{
    public bool IsDeleted { get; set; }   
}

public static class EntityConfigurationExtensionISoftDeletable
{
    public static void ApplyTrait<TEntity, TSoftDeletable>(this EntityTypeBuilder<TEntity> modelBuilder) where TEntity : class, ISoftDeletable 
        where TSoftDeletable: ISoftDeletable
    {
        modelBuilder.Property(x => x.IsDeleted)
            .HasDefaultValue(false)
            .IsRequired();
    }
}

Step 2. Make your entity to be a partial class

public partial class MyEntity 
{
    // your entity definion here    
}

Step 3. Add the trait to your entity thru entity configuration

public class MyEntityConfigurationConfiguration
{    
    public void Configure(EntityTypeBuilder<MyEntity> builder)
    {
        builder.ToTable("MyEntity");
        
        builder.ApplyTrait<MyEntity, ISoftDeletable>();
        
        // rest of your entity configuration here
    }
}

The ApplyTrait method is both - adding the necessary configuration to the entity configuration and informs the code generator to copy the properties from the trait interface to the generated part of the entity class.

Result

In the result you'll get generated partial class with the properties from the trait interface:

// <auto-generated>
public partial class MyEntity : ISoftDeletable
{
    public System.bool IsDeleted { get; set; }
}
// </auto-generated>