ASP.NET Core updates in .NET 6 Preview 1

[Smilefounder]

ASP.NET Core updates in .NET 6 Preview 1

Major work planned in ASP.NET Core in .NET 6

.NET 6 is using an open planning process, so you can see all of the major themes planned for this release on the Blazor-based themesof.net website. In addition to these top-level themes, we expect to deliver many user driven improvements to the platform as well. You can find a list of the major work planned for ASP.NET Core in .NET 6 in our roadmap issue. Here’s a sampling of some of the major ASP.NET Core features planned for the .NET 6 release:

• Hot reload: Quickly make UI and code updates to running apps without loosing app state for faster and more productive developer experience.
• Micro APIs: Simplify building API endpoints with much less code and ceremony.
• Single-file publishing: Build small, standalone, high-performance apps and services.
• WebAssembly ahead-of-time (AoT) compilation: Compile .NET code in Blazor WebAssembly apps directly to WebAssembly when publishing for significantly improved runtime performance.
• Updated single-page app (SPA) support Update SPA integration in ASP.NET Core to work seamlessly with the latest modern front-end JavaScript frameworks.
• Blazor hybrid desktop apps: Combine the best of Blazor and .NET Multi-platform App UI to build cross-platform hybrid desktop apps.
• HTTP/3: Add support for HTTP/3 and QUIC in ASP.NET Core supported servers.

We welcome feedback and participation in the planning and design process on GitHub.

What’s new in ASP.NET Core in .NET 6 Preview 1?

• Support for IAsyncDisposable in MVC
• DynamicComponent
• Input ElementReference exposed on relevant components
• dotnet watch now does dotnet watch run by default
• Nullable reference type annotations

Get started

To get started with ASP.NET Core in .NET 6 Preview 1 install the .NET 6 SDK.

Upgrade an existing project

To upgrade an existing ASP.NET Core app from .NET 5 to .NET 6 Preview 1:

• Update the target framework for your app to net6.0.
• Update all Microsoft.AspNetCore.* package references to 6.0.0-preview.1.*.
• Update all Microsoft.Extensions.* package references to 6.0.0-preview.1.*.

See the full list of breaking changes in ASP.NET Core for .NET 6.

Support for IAsyncDisposable in MVC

You can now implement IAsyncDisposable on controllers, page models, and view components to asynchronously dispose of resources.

DynamicComponent

DynamicComponent is a new built-in Blazor component that can be used to dynamically render a component specified by type.

<DynamicComponent Type="@someType" />

Parameters can be passed to the rendered component using a dictionary:

<DynamicComponent Type="@someType" Parameters="@myDictionaryOfParameters" />

@code {
    Type someType = ...
    IDictionary<string, object> myDictionaryOfParameters = ...
}

Input ElementReference exposed on relevant components

The relevant built-in input Blazor components now expose a convenient ElementReference to the underlying input, which simplifies common scenarios like setting the UI focus on the input. The affected components are InputCheckbox, InputDate, InputFile, InputNumber, InputSelect, InputText, and InputTextArea.

dotnet watch now does dotnet watch run by default

Running dotnet watch will now run dotnet watch run default, saving on precious typing time.

Nullable Reference Type Annotations

We have been applying nullability annotations to parts of ASP.NET Core. A significant number of new APIs were annotated in .NET 6 Preview 1.

By utilizing the new feature in C# 8, ASP.NET Core can provide additional compile-time safety in the handling of reference types like protecting against null reference exceptions. Projects that have opted in to using nullable annotationes may see new build-time warnings from ASP.NET Core APIs.

To enable nullable reference types, you can add the following property to your project file:

<PropertyGroup>
    <Nullable>enable</Nullable>
</PropertyGroup>

For more information, see Nullable reference types.

.NET 6.0.0 Preview 1 - February 17, 2021

The .NET 6.0.0 Preview 1 and .NET SDK 6.0.100-preview.1.21103.13 releases are available for download. The latest 6.0 release is always listed at .NET 6.0 Releases.

What's new in .NET 6 Preview 1

.NET 6 is the next major release of .NET following .NET 5.0. You can see some of the new features available with .NET 6 Preview 1 at dotnet/core #5853.

See the .NET, EF Core and ASP.NET Core blogs for additional details.
Here is list of some of the additions and updates we're excited to bring in Preview 1.

• EntityFramework Core: bugs | features
• .NET SDK bugs

Downloads

	SDK Installer1	SDK Binaries1	Runtime Installer	Runtime Binaries	ASP.NET Core Runtime	Windows Desktop Runtime
Windows	x86 | x64 | Arm64	x86 | x64 | Arm64	x86 | x64 | Arm64	x86 | x64 | Arm64	x86 | x64 | Hosting Bundle2	x86 | x64
macOS	x64	x64	x64	x64	x64	-
Linux	Snap and Package Manager	x64 | Arm | Arm64 | x64 Alpine	Packages (x64)	x64 | Arm | Arm64 | Arm64 Alpine | x64 Alpine	x641 | Arm1 | Arm641 | x64 Alpine	-
	Checksums	Checksums	Checksums	Checksums	Checksums	Checksums

1. Includes the .NET Runtime and ASP.NET Core Runtime
2. For hosting stand-alone apps on Windows Servers. Includes the ASP.NET Core Module for IIS and can be installed separately on servers without installing .NET Runtime.

The .NET SDK includes a matching updated .NET Runtime. Downloading the Runtime or ASP.NET Core packages is not needed when installing the SDK.

You can check your .NET SDK version by running the following command. The example version shown is for this release.

$ dotnet --version
6.0.100-preview.1.21103.13

Mobile Workload Downloads

.NET 6 introduces Android and iOS SDKs for developing native mobile applications. These provide the foundational mobile pieces for the new .NET Multi-platform App UI. See dotnet/net6-mobile-samples for additional setup instructions and sample mobile projects you can run today.

	Android SDK Installer	iOS SDK Installer
Windows	x64	x64
macOS	x64	x64

Visit .NET Documentation to learn about .NET, for building many different types of applications.

Docker Images

The .NET Docker images have been updated for this release. The .NET Docker samples show various ways to use .NET and Docker together. You can use the following command to try running the latest .NET 6.0 release in containers:

docker run --rm mcr.microsoft.com/dotnet/samples

The following repos have been updated.

• dotnet/sdk: .NET SDK
• dotnet/aspnet: ASP.NET Core Runtime
• dotnet/runtime: .NET Runtime
• dotnet/runtime-deps: .NET Runtime Dependencies
• dotnet/samples: .NET Samples

Visual Studio Compatibility

You need Visual Studio 16.9 Preview 4 or later to use .NET 6.0 on Windows. On macOS, you need the latest version of Visual Studio for Mac. The C# extension for Visual Studio Code supports .NET 6.0 and C# 9.

Feedback

Your feedback is important and appreciated. We've created an issue at dotnet/core #5967 for your questions and comments.