Learn About .NET 9 Preview 7 Released

Check Out the Latest .NET 9 Preview!

Microsoft has just released the seventh preview of .NET 9, bringing significant enhancements across various components like the .NET Runtime, SDK, libraries, C#, ASP.NET Core, Blazor, and .NET MAUI. Here are some of the key improvements:

Libraries

BinaryFormatter Removal: Complete.
ReadOnlySpan<char>.Split(): Now supports enumeration.
Debug.Assert: Reports assert condition by default.
Guid.CreateVersion7: Enables creating GUIDs with a natural sort order.
X.509 Certificate Loading: Changes implemented.
XPS Documents: Support is provided by the XPS virtual printer.

Runtime

Post-Indexed Addressing on ARM64: Implemented.
Object Stack Allocation for Boxes: Introduced.
GC Dynamic Adaptation: Adapts to application sizes.

C#

OverloadResolutionPriority Attribute: Prioritizes better overloads.

ASP.NET Core

SignalR and Microsoft.AspNetCore.OpenApi: Support for trimming and Native AOT.
Transformer Registration APIs: Improved.
Problem and ValidationProblem Result Types: Enhanced construction.
OpenIdConnectHandler: Support for Pushed Authorization Requests (PAR).
Data Protection: Support for deleting keys.
Kestrel: Improved connection metrics and customizable named pipe endpoints.

.NET MAUI

HybridWebview: Introduced.
TitleBar Control and Window.TitleBar: New for Windows.
CollectionView & CarouselView: Improvements with a new handler for iOS and Mac Catalyst.
ActivateWindow: Ability to bring a window to the foreground.
BackButtonBehavior: OneWay binding mode.
BlazorWebView: Backward compatibility host address.
ProcessTerminated Event: New on WebView Control.
Lifecycle Methods: For remote notifications on iOS & Mac Catalyst.
Xcode Sync: For CLI and Visual Studio Code.

Download the preview and start working on it to understand the new features and enhancements better.