Visual Studio Code, Flatpak, and C#: A Guide

It took me way too long to figure this out, so I figured I’d write a concise tutorial for anyone else who wants to do C# development using Visual Studio Code installed via flatpak.

SDK Installation

You’ll need to install two SDK extensions:

• flatpak install org.freedesktop.Sdk.Extension.dotnet5
• flatpak install org.freedesktop.Sdk.Extension.mono6

Flatpak Configuration

Two environment variables need to be set for Visual Studio Code to find the .NET SDK. You can use flatpak override --env VARIABLE=VALUE com.visualstudio.code or, if you’d prefer a GUI, use the Flatseal app.

The variables are:

• PATH=/app/bin:/usr/bin:/usr/lib/sdk/dotnet5/bin
• DOTNET_ROOT=/usr/lib/sdk/dotnet5

Visual Studio Code Configuration

Next, restart Visual Studio Code and install the C# extension. Go to the Extensions pane on the left (the little building blocks icon), search “C#”, and install the official extension by Microsoft.

Then go to File -> Preferences -> Settings, search “Mono Path”, and click “Edit in settings.json”. Set it to /usr/lib/sdk/mono6. Then go back to the Settings tab and set “Use Global Mono” to “always”.

That should do it! You might need to restart OmniSharp or Visual Studio Code first, but the C#/.NET tools should work now. Hopefully this process will become easier in the future.