Update to .NET 10

[MrJul]

What does the pull request do?

This PR updates Avalonia to .NET 10.
The .NET 10 RC2 SDK or later is needed to build the solution.

Main changes

• Projects target .NET 10 and .NET 8 (up from .NET 8 and .NET 6).
  • XamlX has been updated to Update .NET to 10.0 kekekeks/XamlX#129
  • New trimming warnings have been handled accordingly.
• C# 14 is used.
  • Variables named field have been renamed.
  • Various LINQ Reverse() calls on arrays have been fixed due to the new implicit Span<T> conversion.
• System.* and Microsoft.* packages have been updated.

Android changes

• Some parameters newly marked as nullable have been handled accordingly.
• Usages of reflection in AvaloniaAccessHelper have been replaced by standard casts.
• AndroidScreens no longer use an experimental API that was removed from AndroidX.

Unchanged (yet)

• .NET Standard 2.0 is still here and will be removed in a subsequent PR.
• Conditional code targeting .NET 6.0 is still in place for now.

[DJGosnell]

• .NET Standard 2.0 is still here and will be removed in a subsequent PR.

Not that I use it, but does this mean dropping dotnet Framework support?

[maxkatz6]

@DJGosnell yes. See our previous announcement #18606

[BobbyCannon]

@maxkatz6 How does dropping .net standard 2.0 affect visual studio extension? I know there is a new SDK for building out of process .NET 8 VS extensions but I think it's lacking a lot of features.

Is this going to be an issue?

I don't think so as long as Avalonia.Remote.Protocol supports .net standard 2.0?

[maxkatz6]

@BobbyCannon our previewer is out-of-process already. But Avalonia.Remote.Protocol is expected to support netstandard, yes, as it provides protocol and dtos to connect to previewer process, and used from both VS and Rider extensions.

[BobbyCannon]

@BobbyCannon our previewer is out-of-process already. But Avalonia.Remote.Protocol is expected to support netstandard, yes, as it provides protocol and dtos to connect to previewer process, and used from both VS and Rider extensions.

I was only concern with protocol. I know the previewer is out of process and I'm not concerned with it.

This is great news, thank you.

[avaloniaui-bot]

You can test this PR using the following package version. 12.0.999-cibuild0059792-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

[avaloniaui-bot]

You can test this PR using the following package version. 12.0.999-cibuild0059798-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

[maxkatz6]

We haven't decided on what to do with .NET 6 target yet, but other than that LGTM