Viu for Visual Studio

Viu for Visual Studio adds editing support for Viu single-file components (.viu) to Visual Studio. One package: the .viu file association, the Viu color theme, and the Viu language server.

Features

• The Viu color theme. Template, markup, and style constructs get their own colors — framework tags, element tags, component tags (bold), directives, attributes and values, interpolation delimiters (bold), tag delimiters, style selectors, and custom properties. Every one of them is a separate, editable entry under "Viu — …" in Tools > Options > Fonts and Colors, so the defaults are a starting point rather than a decision made for you
• Your C# theme inside a component. The @script block, {{ interpolations }}, and binding expressions color with Visual Studio's own C# classifications, so embedded code looks exactly like the C# in the file next to it
• .viu opens in the right editor automatically. The package registers the file extension, so there is no per-file Open With step, and the Viu logo identifies components in Solution Explorer and editor tabs
• Auto-closing that knows which section you are in. {, (, and [ pair everywhere — typing { twice gives you {{}} for an interpolation. Quotes pair only where they mean a string, so an apostrophe in template prose stays an apostrophe. Typing > after an open tag inserts its end tag with the caret between them, </ completes the nearest unclosed element, and <!-- completes to <!-- | -->. Nothing fires inside @script or <style>, where > is a generic argument or a CSS child combinator, and void elements such as <br> insert nothing
• Diagnostics for malformed single-file-component block structure
• Completion for block headers and options, common template elements, directives, events, CSS properties, Context.*, and Reactive.*
• Completion and authored-rule hover for class selectors declared in the component's own <style> blocks, inside template class values
• Hover documentation for core Viu concepts
• Full and incremental document synchronization through an isolated language-server process, so the Viu parsers and Roslyn never run inside Visual Studio itself

Requirements

• Visual Studio 2022 17.14 or newer, or Visual Studio 2026
• An x64 or ARM64 Windows installation

The extension includes the matching self-contained language server, so no separate .NET runtime is required. The Visual Studio core editor is the only prerequisite component; C# support enhances the colors inside @script but is not required.

Preview status

This extension is currently in preview. Its first release provides syntax-aware editing. Roslyn-backed C# completion, component discovery, navigation, rename, references, and source-mapped compiler diagnostics are planned for later releases.

Viu also reads the tag-based .vue single-file-component container, and its language server routes .vue documents in Viu SDK projects. That capability is not surfaced by this Visual Studio package: Visual Studio's own Web Tools owns the .vue file extension, and displacing it is a separate decision. .vue editing support in Visual Studio may follow in a later release.

Report problems and follow development in the Viu repository.