nclnclncl / reflection

Reflection with source generator

Reflection

Why

With the development of .NET, there is an increasing need for AOT Native in many applications. However, reflection and dynamic code pose obstacles to AOT deployment. Source generators can effectively this issue. For example, System.Json.Text use SourceGenerator to handle object serialization. However, these implementations are specific to individual businesses and cannot be easily generalized.

SourceReflection aims to provide a more universal solution, offering AOTable Reflection support to more developers without the need for repetitive source generator implementation.

Supports

• Field
• Property
• Method
• Constructor

Installing Reflection

Install-Package SourceGeneration.Reflection -Version 1.0.0-beta1.240215.1

dotnet add package SourceGeneration.Reflection --version 1.0.0-beta1.240215.1

Start

Add SourceReflectionAttribute to your class

using SourceGeneration.Reflection;

[SourceReflection]
public class Goods
{
    private int Id { get; set; }
    public string Name { get; private set; }
    public double Price { get; set; }

    internal void Discount(double discount)
    {
        Price = Price * discount;
    }
}

using SourceGeneration.Reflection;

// Get TypeInfo
var type = SourceReflector.GetType(typeof(Goods));

// Get default ConstructorInfo and create a instance
var goods = (Goods)type.GetConstructor([]).Invoke([]);

// Get PropertyInfo and set value
type.GetProperty("Id").SetValue(goods, 1); // private property
type.GetProperty("Name").SetValue(goods, "book"); // private property setter
type.GetProperty("Price").SetValue(goods, 3.14); // public property

// Output book
Console.WriteLine(goods.Name);
// Output 1
Console.WriteLine(type.GetProperty("Id").GetValue(goods));
// Output 3.14
Console.WriteLine(goods.Price);

// Get MethodInfo and invoke
type.GetMethod("Discount").Invoke(goods, [0.5]);
// Output 1.57
Console.WriteLine(goods.Price);

Without Attribute

You can also without using SourceReflectionAttribute for reflection

public class Goods
{
    private int Id { get; set; }
    public string Name { get; private set; }
    public double Price { get; set; }

    internal void Discount(double discount)
    {
        Price = Price * discount;
    }
}

Use SourceReflector

using SourceGeneration.Reflection;

// Get TypeInfo and allow Runtime Reflection
var type = SourceReflector.GetType(typeof(Goods), true);

var goods = (Goods)type.GetConstructor([]).Invoke([]);
type.GetProperty("Id").SetValue(goods, 1); // private property
type.GetProperty("Name").SetValue(goods, "book"); // private property setter
type.GetProperty("Price").SetValue(goods, 3.14); // public property
type.GetMethod("Discount").Invoke(goods, [0.5]);

It can work properly after AOT compilation. DynamicallyAccessedMembers allows tools to understand which members are being accessed during the execution of a program.

Use Custom Attribute

You can create a custom attribute to indicate to the source generator which types need to be reflected.

Edit your project .csproj

<!-- define your Attribute -->
<PropertyGroup>
  <DisplaySourceReflectionAttribute>System.ComponentModel.DataAnnotations.DisplayAttribute</DisplaySourceReflectionAttribute>
</PropertyGroup>

<!-- set property visible  -->
<!-- property name must be endswith 'SourceReflectionAttribute'  -->
<ItemGroup>
  <CompilerVisibleProperty Include="DisplaySourceReflectionAttribute" />
</ItemGroup>

Now you can use the DisplayAttribute to inform the source generator that you need to reflect it.

[System.ComponentModel.DataAnnotations.Display]
public class Goods
{
    private int Id { get; set; }
    public string Name { get; private set; }
    public double Price { get; set; }
}

Samples

• HelloWord example demonstrates some basic uses of SourceReflection.

• CsvWriter is a aotable sample library, it provider only one method to export .csv file

• CustomLibrary example demonstrates how to use SourceReflection to publish your NuGet package and propagate your attributes.