ASP.​NET Core in .NET 6 - Overview

.NET 5 was released just about 3 months age and Microsoft announced the first preview of .NET 6 last week. This is really fast. Actually, they already started working on .NET 6 before version 5 was released. But it is anyway cool to have a preview available to start playing around. Also, the ASP.NET team wrote a new blog post. It is about ASP.NET Core updates on .NET 6.

I will take the chance to have a more detailed look into the updates and the new feature. I'm going to start a series about those updates and features. This is also a chance to learn what I need to rewrite, If I need to update my book that recently got published by Packt.

Install .NET 6 preview

At first I'm going to download ..NET 6 preview from and install it on my machine.


I chose the x64 Installer for Windows and started the installation


After the installation is done the new SDK is available. Type dotnet --info in a terminal:


Be careful

Since I didn't add a global.json yet, the .NET 6 preview is the default SDK. This means I need to be careful if I want to create a .NET 5 project. I need to add a global.json every time I want to create a .NET 5 project:

dotnet new globaljson --sdk-version 5.0.103

This creates a small JSON file that contains the SDK version number in the current folder.

  "sdk": {
    "version": "5.0.103"

Now all folder and subfolder will use this SDK version.

Series posts

This series will start with the following topics:

Preview 1

ASP.NET Core Updates in .NET 6 preview 1

Preview 2

ASP.NET Core Updates In .NET 6 preview 2

Preview 3

ASP.NET Core updates in .NET 6 Preview 3

Preview 4

  • Introducing minimal APIs
  • Async streaming
  • HTTP logging middleware
  • Use Kestrel for the default launch profile in new projects
  • IConnectionSocketFeature
  • Improved single-page app (SPA) templates
  • .NET Hot Reload updates
  • Generic type constraints in Razor components
  • Blazor error boundaries
  • Blazor WebAssembly ahead-of-time (AOT) compilation

Preview 5

  • NET Hot Reload updates for dotnet watch
  • ASP.NET Core SPA templates updated to Angular 11 and React 17
  • Use Razor syntax in SVG foreignObject elements
  • Specify null for Action and RenderFragment component parameters
  • Reduced Blazor WebAssembly download size with runtime relinking
  • Configurable buffer threshold before writing to disk in Json.NET output formatter
  • Subcategories for better filtering of Kestrel logs
  • Faster get and set for HTTP headers
  • Configurable unconsumed incoming buffer size for IIS

Preview 6

  • Improved Blazor accessibility
  • Required Blazor component parameters
  • Efficient byte array transfers for JavaScript interop
  • Optional parameters for view component tag helpers
  • Angular template updated to Angular 12
  • OpenAPI support for minimal APIs
  • Inject services into minimal APIs without [FromServices] attribute
  • Configure the accept socket for Kestrel
  • IHttpActivityFeature
  • Long running activity tag for SignalR connections
  • WebSocket compression
  • SignalR WebSockets TestServer support
  • New OnCheckSlidingExpiration event for controlling cookie renewal
  • ClientCertificateMode.DelayCertificate

Preview 7

  • Parity with existing experiences for minimal APIs
  • Added IResult implementations for producing common HTTP responses
  • Support Request, Response and User for minimal actions
  • Minimal host and template improvements
  • Supply Blazor component parameters from the query string
  • Replace the current URI in the browser history from Blazor
  • New DynamicComponent.Instance property
  • Blazor streaming interop from JavaScript to .NET
  • Large file upload & faster file uploads with Blazor
  • Modify HTML <head> content from Blazor components
  • Support for the multiple attribute on <select> elements in Blazor
  • Support for HTTP/3 in Kestrel
  • QUIC support moved to the shared framework
  • Allow control over Activity creation
  • Support for non-ASCII characters in Kestrel response headers
  • Add W3CLogger
  • Add authentication expiration option to SignalR

(I will update this list as soon I add a new post or as soon Microsoft adds a new release).2

If you found any error on this post, feel free to tell me: Add a comment below, file an issue on GitHub or edit this page on GitHub and send me an PullRequest.

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Jürgen Gutsch Jürgen Gutsch
.NET junkie, addicted to web and software development, clean coder, MVP for Developer Technologies