A Comprehensive Guide for Enterprise Developers on .NET 9

Overview

It is Microsoft's tradition to empower developers to develop robust, scalable, and high-performance applications with .NET 9. In this article, we'll explore how .NET 9 and C# 13 are shaping the future of enterprise development, with practical examples and use cases, along with exciting new features in C# 13.

What’s New in .NET 9?

Performance Advancements

.NET 9 introduces enhanced Ahead-of-Time (AOT) compilation, which helps applications start quickly and consume less memory.

Here's an example of how to compile AOT

To enable AOT compilation, follow these steps:

dotnet publish -c Release -r win-x64 --self-contained -p:PublishAot=true  

Cloud-Native Enhancements

. NET 9 simplifies the development of cloud-native applications by offering better Kubernetes integration and improved microservices capabilities.

An example of a minimal microservice API

var app = WebApplication.CreateBuilder(args).Build();  
app.MapGet("/hello", () => "Hello, .from Ziggy Rafiq using C#13 and .NET 9!");  
app.MapPost("/add", (int x, int y) => Results.Json(new { Result = x + y }));  
await app.RunAsync();  

Improved Diagnostics and Monitoring

In .NET 9, built-in diagnostics like dotnet trace and dotnet monitor are more powerful, allowing developers to easily trace and debug cloud applications.

Introducing C# 13 Features

Advanced Pattern Matching: List Patterns

The use of list patterns allows you to match and deconstruct arrays and collections.

An array is filtered using the following code example

int[] numbers = { 1, 2, 3, 4, 5 };  

if (numbers is [1, .., 5])  
{  
    Console.WriteLine("Array starts with 1 and ends with 5!");  
}  

Inline Lambdas

Reduce verbosity by simplifying lambda expressions with inline syntax.

Inline Lambda with LINQ as an example

var numbersLinq = Enumerable.Range(1, 10);
var squares = numbersLinq.Select(static x => x * x);

Console.WriteLine("Squares of numbers from 1 to 10:");

foreach (var square in squares)
    Console.WriteLine(square);

Span<T> Enhancements

Efficiently manage memory with improved Span<T> support.

The following code example shows how to use Span<T>

Span<int> span = stackalloc int[] { 1, 2, 3, 4, 5 };
span[0] = 42;

Console.WriteLine("Elements in the span:");
for (int i = 0; i < span.Length; i++)
    Console.WriteLine(span[i]);
   
Console.WriteLine(span[0]);  // Outputs: 42  

Building Enterprise Applications with .NET 9

Scenario: High-Performance APIs

The minimal APIs in .NET 9 make it easier to develop high-performance endpoints with minimal boilerplate.

Example of a secured API using JWT authentication

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddAuthentication("Bearer")
    .AddJwtBearer(options =>
    {
        
        options.Authority = "https://need-auth-server.com-here";
                
        options.TokenValidationParameters.ValidateAudience = false;
    });

var app = builder.Build();


app.UseAuthentication();
app.UseAuthorization();

app.MapGet("/secure", () => "Secure Data")
   .RequireAuthorization();

await app.RunAsync();  

The Blazor Enterprise Dashboard Scenario

Thanks to its significant performance improvements, a dynamic dashboard can be created using Blazor in .NET 9.

Real-Time Dashboard with Blazor code example

@page "/dashboard"  

<h3>Real-Time Metrics</h3>  

<p>CPU Usage: @cpuUsage%</p>  

@code {  
    private int cpuUsage;  

    protected override async Task OnInitializedAsync()  
    {  
        while (true)  
        {  
            cpuUsage = new Random().Next(0, 100);  // Simulated data  
            StateHasChanged();  
            await Task.Delay(1000);  
        }  
    }  
}  

Security and Compliance in .NET 9

.NET 9 includes built-in support for modern security protocols like OAuth2 and FIDO2.

This code example shows how to authenticate using OAuth2

builder.Services.AddAuthentication("Bearer")
    .AddJwtBearer(options =>
    {
        options.Authority = "https://login.microsoftonline.com/our-tenant-id";
        options.Audience = "our-api-scope";
    });

Migration Strategy: Moving to .NET 9

1. Evaluate Your Codebase: Use tools like the .NET Upgrade Assistant to evaluate your codebase.
2. Incremental Migration: The incremental migration method involves migrating libraries and services.
3. Testing and Validation: Make sure functionality is tested and validated using NUnit by writing comprehensive unit tests.

This is an example of a NUnit test for a feature of .NET 9

[Test]  
public void TestAddEndpoint()  
{  
    var result = Add(2, 3);  
    Assert.AreEqual(5, result);  
}  

 namespace DemoConsole;
public static class Demo
{
    public static int Add(int x, int y) => x + y;
}

Summary

For enterprise developers, .NET 9 and C# 13 offer improved performance, scalability, and developer-friendliness. We invite you to learn more about these advancements and future-proof your applications to meet future demands.

I hope you have enjoyed reading this article.My GitHub repository https://github.com/ziggyrafiq/DotNet9_EnterpriseGuide  has the code for this article. Also, join the growing community of .NET enthusiasts at C# Corner by sharing your experiences and projects with .NET 9 and C# 13!