Avalonia is a cross-platform XAML-based UI framework providing a flexible styling system and supporting a wide range of Operating Systems such as Windows via .NET Framework and .NET Core, Linux via Xorg and macOS. It uses AXAML format, which is a variant of XAML.
This Visual Studio Code Extension contains support for AXAML like autocompletion, live previewer, document outlines, etc.
Avalonia is a registered trademark of AvaloniaUI OÜ. This extension is independent and unaffiliated with Avalonia.
This repository is a fork of the original Avalonia for VS Code extension by Avalonia UI. Our goal is to actively maintain and enhance the developer experience in Visual Studio Code by:
- Keeping the extension up to date with new Avalonia releases
- Improving performance, reliability, and cross‑platform behavior
- Adding new productivity features (outline view, visual designer, smarter completion, diagnostics, etc.)
- Responding to community feedback and accelerating fixes
Issues and feature requests are welcome—your input helps shape the roadmap.
Follow the contribution guide if you want to help us build the extension.
For consistent formatting of your AXAML files, we recommend optionally installing the community XAML Styler extension (dabbinavo.xamlstyler). The first time you use this extension you'll receive a prompt; you can also find it manually in the Extensions view by searching for "XAML Styler". This extension is optional—the AXAML features work without it.
You can create a new Avalonia project directly from the Visual Studio Code
Additionally, you can create a project from the command line too, with the command:
dotnet new avalonia.app -o MyApp
This will create a new folder called MyApp with your application files. You can install Avalonia project templates with following command, if you do not have them installed already:
dotnet new install Avalonia.Templates
Finally open the MyApp folder in the VS Code, open any AXAML file to activate the extension and code completion.
NOTE: You must build the project once to enable code completion.
After you load the project in the VS Code, you can click on Show Preview button on the editor toolbar (1)
The previewer will prompt you to build your project if needed.
The previewer will refresh when you switch between multiple xaml files, unlike Visual Studio for Windows or Rider, VS Code will reuse the single preview window.
- New: the previewer supports a DPI‑aware scaling mode that renders crisper UI previews. When
axaml.previewer.transportModeis set totcp(the default), the previewer sends raw pixel frames over a TCP channel and the extension renders them on a canvas using the editor's DPI settings for sharper, correctly scaled output. With your mouse, holdAltand scroll on the preview canvas to adjust the zoom level. - If you experience issues with embedded content or prefer the previewer's built‑in HTML server, set
axaml.previewer.transportModetohtmlto embed the preview in an iframe instead.
Rich syntax highlighter and contextual code completion will make it lot easier to read and write AXAML files
The AXAML files in the VS Code are showed with document outlines, allowing you to collapse and expand sections of your AXAML files for better readability.
AXAML: Toggle verbose AXAML logs(axaml.toggleVerboseLogs)AXAML: Show preview(axaml.showPreviewToSide)AXAML: Create previewer assets(axaml.createPreviewerAssets)AXAML: Create a new Avalonia Project(axaml.newProject)AXAML: Show solution discovery info(axaml.showSolutionDiscoveryInfo)AXAML: Open solution model JSON(axaml.openSolutionModelJson)
axaml.completion.buildConfigurationPreference– Preferred build configuration for completion (Debug / Release / Auto)axaml.trace.verbose– Enable verbose AXAML server side logs (assembly scanning, metadata fallback)axaml.trace.server– LSP protocol tracing (messages / verbose)axaml.misc.suppressXamlStylerRecommendation– Suppress prompt recommending XAML Styler extensionaxaml.previewer.emitBinlog– Emit MSBuild binary log when building previewer assetsaxaml.previewer.runDotnetInfo– Run 'dotnet --info' before building previewer assetsaxaml.previewer.transportMode– Previewer transport mode. Default istcp: the previewer sends raw pixel frames over a TCP channel and the extension renders them on a canvas (provides crisper, DPI‑aware scaling). Set tohtmlto embed the previewer's HTTP server in an iframe instead.
- Default: the extension now uses the
XamlToCSharpGenerator(AXSG) language server by default. AXSG focuses specifically on AXAML workflows and offers improved completion, inline C# projections, and tighter previewer integration. - Files targeted: the extension and AXSG are scoped to AXAML files only (file type
axaml). They do not activate on genericxamlfiles. - To change the server: set
axaml.languageServerto eitherXamlToCSharpGeneratororAxamlLanguageServerin your settings. - To point to a custom server binary or DLL, set
axaml.languageServerPathto an absolute path; this overrides theaxaml.languageServerselection.
NOTE: AXSG language server is created by Wiesław Šoltés, and released under MIT license. Axaml language server created by AvaloniaUI is not recommended but can be turned on if needed.
NOTE: AXSG language server is still an early preview. It might experience instability such as
- Report many warnings (in AXSG0111 category or others). Please ignore them.
- Long delay before the first change to semantic highlighting and completion.
- The experimental hot reload based previewer integration is disabled due to stability issues. Please use the existing TCP or HTML transport previewer integration instead.
You can report directly to this repo.
This includes a short feature comparison between the two language servers shipped with the extension.
| Feature | AxamlLanguageServer | AXSG/XamlToCSharpGenerator (default) |
|---|---|---|
| Completion | Yes — engine-backed, lightweight; initializes metadata from project assembly when available | Yes — richer, project/semantic-aware completions via language service |
| Hover / Quick info | Yes (standard handlers) | Yes (semantic, can include generated C# projection data) |
| Document symbols / outline | Yes (DocumentSymbolHandler, XmlOutlineHelper) |
Yes (semantic model-driven symbols) |
| Go-to-definition / References / Rename | Basic go-to (file-level/project metadata dependent) | Full project-aware navigation, references, rename/refactor support via Roslyn integration |
| Semantic tokens | Not primary; basic syntax features provided | Supported (semantic engine provides richer tokens/semantic coloring) |
| Inline C# projection | No (focuses on AXAML editing) | Supported (projects show inline C# projection / mapping in some flows) |
| Code generation (XAML→C#) | Not core responsibility (editor assistance only) | Core capability (Xaml→C# generator toolchain integrated) |
| Project awareness | Limited (reads simple project metadata / assembly) | High (MSBuild/Roslyn-aware, works with full project model) |
| Footprint / startup | Lightweight, smaller binary set | Heavier — many assemblies, larger runtime requirements |
| Runtime requirements | .NET runtime (packaged .dll under axamlServer) |
.NET runtime + MSBuild/Roslyn runtime pieces; recommended as installed tool or packaged axsgServer |
| Update path / extensibility | Source present in repo — easy to modify and rebuild | Packaged binaries shipped with extension; source available in XamlToCSharpGenerator/ but typically published as artifacts |
| Typical use-case | Fast editor features for AXAML editing; easy to inspect and patch | Deep project-aware language service, codegen, and advanced refactor/navigation |
| Status | Stable | Early preview (expect warnings, some instability, etc.) |
Detailed information can be found on this page.
Copyright (c) 2023 AvaloniaUI
Copyright (c) 2025-2026 LeXtudio Inc.
Copyright (c) 2026 Wiesław Šoltés