Facet 1.0.0

Facet

Facet is a compile-time source generator that creates partial classes from existing types — by copying only the members you want.

Exclude properties, include public fields, add your own members, or generate a constructor — all with a single [Facet] attribute.

Use Facet to build lightweight DTOs, API shapes, or UI-bound view models without writing boilerplate or mapping code.

No base classes. No reflection. No runtime cost.

Features

• ✅ Exclude properties and fields with nameof(...)
• ✅ Include public fields (optional)
• ✅ Generate constructors that copy from the source type
• ✅ Add your own extra properties in the generated type
• ✅ No base class or interface required
• ✅ No runtime reflection — compile-time only
• ✅ Works with or without namespaces

Quick Start

1. Install

dotnet add package Facet

2. Use

using Facet;

public class Person
{
    public string Name { get; set; }
    public string Email { get; set; }
    public int Age { get; set; }
}

[Facet(typeof(Person), nameof(Person.Email))]
public partial class PersonWithoutEmail
{
}

3. What gets generated

public partial class PersonWithoutEmail
{
    public string Name { get; set; }
    public int Age { get; set; }
}

4 Extending

[Facet(typeof(Person),
 excludes: new [] { nameof(Person.Email), nameof(Person.Age) } )]
public partial class PersonNameWithNote
{
    public string Note { get; set; }
}

Becomes:

public partial class PersonNameWithNote
{
    public string Name { get; set; }
    public string Note { get; set; }
}

5 Constructors

[Facet(typeof(Person), nameof(Person.Email), GenerateConstructor = true)]
public partial class PersonDto { }

Now you can do:

var person = new Person();
var dto = new PersonDto(person);

Which results in:

public partial class PersonDto
{
    public string Name { get; set; }
    public int Age { get; set; }
    public Guid RawId;

    public PersonDto(Person source)
    {
        this.Name = source.Name;
        this.Age = source.Age;
        this.RawId = source.RawId;
    }
}

Why Facet?

Why Facet? No mappings. No reflection. No bloated libraries.

Just clean, compile-time class shaping — with minimal syntax and full control.

Package Info

• Target frameworks: netstandard2.0
• Supports: .NET Core 3.1+, .NET 5+, .NET 6+, .NET 7, .NET 8
• Analyzer delivery: Source generator is embedded in the NuGet package