A First Look at .NET 6 and C# 10

As we approach the final release in November, the picture of .NET 6 is becoming crystal clear, and it's an exciting one. Building on the unification work started in .NET 5, .NET 6 is shaping up to be a landmark Long-Term Support (LTS) release, packed with performance improvements, new application types, and a host of language features in C# 10 designed to dramatically improve developer productivity.

Let's take a look at some of the most anticipated features that have been demonstrated in the preview releases.

.NET 6: The Platform

1. Hot Reload

This is perhaps the most talked-about productivity feature. Hot Reload allows you to make changes to your application's source code while it's running, without needing to restart it. The changes are applied automatically, allowing you to see the effect of your edits in real-time. This feature is set to work across a wide range of application types, including web apps (ASP.NET Core), desktop apps, and mobile apps.

2. Minimal APIs

For years, creating a simple web API in ASP.NET Core involved a significant amount of boilerplate: controllers, Startup.cs, and multiple configuration methods. .NET 6 introduces Minimal APIs, a new, streamlined way to build APIs with just a few lines of code.

// A complete web API in Program.cs
var app = WebApplication.Create(args);
app.MapGet("/hello", () => "Hello, World!");
app.Run();

This, combined with C# 10's top-level statements, dramatically lowers the barrier to entry for building small services and microservices in .NET.

3. .NET MAUI (Multi-platform App UI)

.NET 6 will see the official release of .NET MAUI, the evolution of Xamarin.Forms. MAUI is a cross-platform framework for creating native UI for desktop and mobile applications from a single, shared C# codebase. It allows you to build applications for Windows, macOS, iOS, and Android, all from one project.

4. Massive Performance Improvements

Continuing the trend from .NET 5, .NET 6 is packed with performance optimizations across the entire stack, from the JIT compiler and garbage collector to core libraries. File I/O, in particular, has been completely re-architected for better performance on modern hardware.

C# 10: The Language

C# 10, which will ship with .NET 6, is focused on simplifying syntax and reducing ceremony.

1. Global Using Directives

To reduce the repetitive list of using statements at the top of every file, you can now declare a using statement as global in one file, and it will apply to your entire project.

// In a file like GlobalUsings.cs
global using System;
global using System.Collections.Generic;
global using System.Threading.Tasks;

2. File-Scoped Namespaces

Another feature to reduce indentation and boilerplate. Instead of wrapping your entire file in a namespace block, you can declare it on a single line.

// No more curly braces for the namespace
namespace MyAwesomeApp.Services;

public class MyService
{
    // ...
}

3. Record Structs

C# 9 introduced record class. C# 10 completes the story by adding record struct, allowing you to create immutable value types with the same concise syntax and compiler-generated methods (like value-based equality) as record classes.

A New Era for .NET

.NET 6 and C# 10 represent a significant leap forward in developer productivity and platform unification. The focus on simplification with features like Minimal APIs and Hot Reload makes .NET more approachable and enjoyable to use than ever before. As an LTS release, .NET 6 is poised to be the foundation of the .NET ecosystem for years to come, providing a stable, high-performance, and unified platform for building any application.