.NET 9 brings a plethora of new features and improvements that promise to enhance developer productivity and application performance. This article dives into the most notable updates, spanning C# 13,ASP.NETCore, EF Core, .NET Aspire, Runtime, AI, SDK, .NET MAUI, and security features.

C# 13: Enhancing Developer Productivity

The latest iteration of the C# language, C# 13, introduces several key features:

• Parms Collection: Simplifies the handling of parameter collections, making code more readable and maintainable.

public void WriteNames(params string[] names)
   => Console.WriteLine(String.Join(", ", names));

WriteNames("Mads", "Dustin", "Kathleen");
WriteNames(new string[] {"Mads", "Dustin", "Kathleen"});
// Both of these Would output: Mads, Dustin, Kathleen

public void WriteNames(params string[] names)
   => Console.WriteLine(String.Join(", ", names));

WriteNames("Mads", "Dustin", "Kathleen");
WriteNames(new string[] {"Mads", "Dustin", "Kathleen"});
// Both of these Would output: Mads, Dustin, Kathleen

• New Lock Type: Introduces a new lock type that provides more flexibility and control over concurrency.

public class MyClass 
{    private object myLock = new object();
   //The following line is the only change
    private System.Threading.Lock myLock = new System.Threading.Lock();
    public void MyMethod() 
    {
        lock (myLock)
        {
           // Your code
        }
    }
}

• New Escape Sequence: Adds new escape sequences for better string handling.

\u001b => \e

• Implicit Indexer Access: Streamlines the process of accessing indexers, enhancing code clarity.

class Program
{ static void Main(){
        var x = new Numbers{
            Values = 
            {
                [1] = 111,
                [^1] = 999  // Works starting in C# 13
            }// x.Values[1] is 111, // x.Values[9] is 999, since it is the last element
        };
      }
}

ASP.NETCore: Modernizing Web Development

ASP.NETCore continues to evolve with a host of new features aimed at improving web application development:

• Static Asset Delivery: Enhancements for more efficient delivery of static assets.

• Improved Security with New API: Strengthened security measures with the introduction of new security APIs.

• OpenAPI Built-in Support: Native support for OpenAPI, simplifying the process of building and documenting APIs.

• Hybrid Cache: A hybrid caching solution to improve application performance.

• Blazor Server Enhancements: Performance and usability improvements for Blazor Server.

EF Core: Advanced Data Management

Entity Framework (EF) Core sees significant updates that enhance data management capabilities:

• Better Cosmos DB Support: Improved support for Azure Cosmos DB, enabling more efficient data operations.

• AOT and Pre-compiled Queries: Support for Ahead-of-Time (AOT) compilation and pre-compiled queries for faster execution.

• Migrations Improvements: Enhanced migration tools to simplify database schema updates.

Libraries: Expanding the Toolkit

.NET 9 includes several library enhancements to broaden the developer toolkit:

• New LINQ Methods: Additional methods for LINQ to provide more powerful query capabilities.

• Cryptography Improvements: Enhanced cryptographic libraries for better security.

• Collection Improvements: Optimizations and new features for collections.

.NET Aspire: Elevating Application Management

.NET Aspire introduces several new features to improve application lifecycle management:

• Tooling Improvements: Enhanced developer tools for better productivity.

• Dashboard UX Enhancements: Improved user experience for the management dashboard.

• Manage Resource Lifecycle: Better management of resource lifecycles.

• Mobile and Responsive Support: Full support for mobile and responsive design.

• Sensitive Properties, Volumes, and Health Checks in Resource Details: More detailed insights into resource properties and health.

• Colorful Console Log: Enhanced console logging with more colors and formats.

• Telemetry User-centric Additions: New telemetry features focused on user behavior.

• Browser Telemetry Support: Support for collecting telemetry from web browsers.

• App Host (Orchestration): Improved application hosting and orchestration capabilities.

• Persistent Containers: Enhanced support for persistent container environments.

Runtime: Boosting Performance and Flexibility

The .NET Runtime sees several updates aimed at improving performance and flexibility:

• Feature Switches Model: A new model for toggling features on and off.

• Performance Improvements: Numerous enhancements to boost runtime performance.

• GC Dynamic Adaptation: Improved garbage collection with dynamic adaptation.

AI: Bridging the Gap to Intelligent Applications

.NET 9 enhances its AI capabilities with new features:

• C# Abstractions Layer: A new layer for better AI abstractions in C#.

• More Pre-built Models: Additional pre-built models for quick AI integration.

• New Tensor Types: Support for new tensor types to facilitate machine learning operations.

SDK: Enhancing Development Workflow

The .NET 9 SDK introduces several new features to streamline the development process:

• Workload Sets: Simplified workload management for various development scenarios.

• Run Unit Tests in Parallel: Support for running unit tests in parallel to speed up testing.

• New Code Analyzers: Additional code analyzers to help maintain code quality.

• File I/O: Better support for asynchronous file I/O operations.

• JSON Serialization Improvements: Enhanced JSON serialization capabilities.

• Cryptography Improvements: Further cryptographic enhancements.

• .NET Install Search Behavior: Improved search behavior for .NET installations.

.NET MAUI: Cross-Platform Development Made Easier

.NET Multi-platform App UI (.NET MAUI) receives updates that facilitate cross-platform development:

• New Controls: Introduction of new UI controls for richer applications.

• Control Enhancements: Improvements to existing controls for better functionality.

Security Features: Fortifying Applications

Security remains a top priority, with .NET 9 introducing several new security features:

• Native AOT (Ahead-of-Time) Compilation for Secure Executables: AOT compilation for more secure executables.

• Improved Authentication and Authorization APIs: Enhanced APIs for better authentication and authorization.

• Improved Code Integrity: Additional measures to ensure the integrity of your code.

.NET 9 is packed with features and improvements that promise to enhance the development experience, boost application performance, and provide more robust security. Whether you're a seasoned developer or just starting, these updates offer valuable tools and capabilities to help you build better software.