Welcome to Net9WhatsNew
Press space to navigate.
Press left arrow to go back.
Press right arrow to go forward.

Online at https://ignatandrei.github.io/Presentations/Net9WhatsNewprez.html
For download https://ignatandrei.github.io/Presentations/Net9WhatsNew.zip

System.Console.WriteLine("Ignat Andrei");
System.Console.WriteLine("Net9WhatsNew");
  

YouTube 5 minutes .NET and tools : http://bit.ly/5MinTools

Book Making Open Source Component : http://bit.ly/NetOpenSourceComponent

Book Copy Paste from StackOverflow : https://amzn.to/2PQ8EDc

Roslyn Source Code Generators with examples : https://ignatandrei.github.io/RSCG_Examples/

Monthly meetings: https://www.meetup.com/Bucharest-A-D-C-E-S-Meetup/

For notes press S
For print ?print-pdf
For all slides press ESC

https://learn.microsoft.com/en-us/dotnet/core/whats-new/dotnet-9/overview

STS release ( supported until May 12, 2026)

• .NET 9 Runtime
• C# 13
• Entity Framework Core
• ASP.NET Core
• Aspire
• Not in this demo : Blazor, WPF, AI, MAUI , F# 9
• Not in this demo : Performance improvements

https://learn.microsoft.com/en-us/dotnet/core/whats-new/dotnet-9/runtime

FeatureSwitchDemo
Base64Demo
BinaryFormatterDemo
OrderedDictionaryDemo
TimeSpanDemo
LinqCountAggregateDemo
SearchValuesDemo
GenerateGuidV7
BigMulDemo
WhenEachDemo

Not in this demo: JSON Serialization/Deserialization: https://learn.microsoft.com/en-us/dotnet/standard/serialization/system-text-json/extract-schema
Multiple JSON :https://learn.microsoft.com/en-us/dotnet/standard/serialization/system-text-json/use-utf8jsonreader#read-multiple-json-documents
DI Choose Constructor: https://learn.microsoft.com/en-us/dotnet/core/whats-new/dotnet-9/libraries#dependency-injection---activatorutilitiescreateinstance-constructor
PersistedAssemblyBuilder, https://learn.microsoft.com/en-us/dotnet/core/whats-new/dotnet-9/libraries#persisted-assemblies

Demo: Whta.csproj

https://learn.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-13

params keyword for collections
new lock object
field keyword
partial properties

Not in this demo

Demo: WhtaCSharp13.csproj , PartialProperties.csproj

https://learn.microsoft.com/en-us/ef/core/what-is-new/ef-core-9.0/whatsnew

	Seeding ( see  BeforeOnConfiguring)
	Order/OrderDescending
	Improvements in SqlGeneration
	AutoCompiled Models	
	

Not Here:
AOT https://learn.microsoft.com/en-us/ef/core/performance/nativeaot-and-precompiled-queries
Demo: EFCoreConsole.csproj, EFCoreDemo.csproj

https://learn.microsoft.com/en-us/aspnet/core/release-notes/aspnetcore-9.0?view=aspnetcore-9.0

		One OpenAPI json, multiple UI 
		Assets: MapStaticAssets
		TypedResults.InternalServerError

		

Not here: SignalR, Blazor, Hybrid Cache
https://learn.microsoft.com/en-us/aspnet/core/release-notes/aspnetcore-9.0?view=aspnetcore-9.0#new-hybridcache-library
Demo:WhatsAspNet.csproj

https://learn.microsoft.com/en-us/dotnet/aspire/whats-new/dotnet-aspire-9?tabs=windows

			WithLifetime(ContainerLifetime.Persistent)
			WaitFor(asp);
			restart
		

Not Here:
https://learn.microsoft.com/en-us/dotnet/aspire/app-host/eventing


Demo: Whta.AppHost.csproj