.NET

.NET Core は Microsoft 製の新しいオープンソース C#, Visual Basic, F# ソフトウェアフレームワークです。先行の .NET Framework と異なり、クロスプラットフォームで動作し近代的なアプリケーションに適した設計が行われています。

インストール

.NET Core で管理されるアプリケーションを実行したいだけの場合は dotnet-runtime パッケージをインストールしてください。

.NET Core でアプリをビルドする場合は dotnet-sdk パッケージもインストールしてください。

Microsoft は .NET Core アプリをビルド・デバッグするときは Electron ベースのオープンソース IDE である Visual Studio Code を使うことを推奨しています。

ヒント: PATH に ~/.dotnet/tools を追加してください。追加しない場合は、 dotnetツールはシェルから使うことができません。

手動による複数バージョンのインストール

You can install multiple versions of the .NET Core SDK or runtime side by side by using the dotnet-install.sh script provided by the .NET Foundation. You can find the documentation of the script here.

For instance, this command would install the latest version found in the "current" channel in /usr/share/dotnet:

# ./dotnet-install.sh --install-dir /usr/share/dotnet -channel Current -version latest

You may want to simulate the installation first by using the -Dryrun flag.

Once installed, you can verify the SDKs available:

$ dotnet --list-sdks                                                                 
2.2.108 [/usr/share/dotnet/sdk]
3.0.103 [/usr/share/dotnet/sdk]
$ dotnet --version
3.0.103

AURによる複数バージョンのインストール

Some of the AUR dotnet packages are made to be installed alongside each other. Only one host package (dotnet-host-bin^AUR or dotnet-host) is needed containing the command-line tool and you can install any of the available SDKs and Runtimes (latest packages of all major versions) next to it. List of compatible packages:

dotnet-host-bin^AUR, dotnet-runtime-bin^AUR, aspnet-runtime-bin^AUR, dotnet-sdk-bin^AUR
dotnet-host-preview^AUR, dotnet-runtime-preview^AUR, aspnet-runtime-preview^AUR, dotnet-sdk-preview^AUR
dotnet-runtime-3.0^AUR, aspnet-runtime-3.0^AUR, dotnet-sdk-3.0^AUR,
dotnet-runtime-2.2^AUR, aspnet-runtime-2.2^AUR, dotnet-sdk-2.2^AUR, dotnet-sdk-2.2-vs2017^AUR
dotnet-runtime-2.1^AUR, aspnet-runtime-2.1^AUR, dotnet-sdk-2.1^AUR

PowerShell Core のインストール

You can install PowerShell Core as a "global" tool also [1] [2]

# dotnet tool install --global PowerShell

to update to current version

# dotnet tool update --global PowerShell

テレメトリ

テレメトリはデフォルトで有効になっていますが、環境変数の設定により無効にできます。DOTNET_CLI_TELEMETRY_OPTOUT=1

トラブルシューティング

It was not possible to find any compatible framework version

If you get the following error when you try to run a newly created project, you no longer need to set a DOTNET_ROOT variable as described in the solutions of various GitHub issues. Arch's dotnet package (as of 3.1) installs it to the Microsoft recommended location of /usr/share/dotnet.

$ dotnet run

It was not possible to find any compatible framework version
The framework 'Microsoft.AspNetCore.App', version '3.1.0' was not found.
  - No frameworks were found.

You can resolve the problem by installing the specified framework and/or SDK.

The specified framework can be found at:
  - https://aka.ms/dotnet-core-applaunch?framework=Microsoft.AspNetCore.App&framework_version=3.1.0&arch=x64&rid=arch-x64

This is caused because the runtime is shipped as a separate package in Arch. You just need to make sure you have the aspnet-runtime package installed as well.

"the required library libhostfxr.so could not be found" error

Some of the dotnet SDK tools (for example libman, dotnet-watch etc.) may expect you to have the environment variable DOTNET_ROOT pre-configured. If it's not, an error like this one could be observed: [3]

A fatal error occurred, the required library libhostfxr.so could not be found.
If this is a self-contained application, that library should exist in [/home/my_user/.dotnet/tools/.store/microsoft.web.librarymanager.cli/1.0.172/microsoft.web.librarymanager.cli/1.0.172/tools/netcoreapp2.1/any/].
If this is a framework-dependent application, install the runtime in the default location [/usr/share/dotnet] or use the DOTNET_ROOT environment variable to specify the runtime location.

The workaround is to manually export DOTNET_ROOT in your shell:

~/.bashrc

export DOTNET_ROOT=/opt/dotnet

SDK specified could not be found

This is believed to caused by a conflict between the Mono and MSBuild SDK libs and the dotnet core ones. To fix this export the path manually in your shell (replacing the version number as necessary) e.g:

~/.bashrc

export MSBuildSDKsPath=$( echo /usr/share/dotnet/sdk/3.*/Sdks );

参照