Roslyn analyzer and Visual Studio extension that helps you promote using directives into the right shared place:

Source	Destination
C# `using` / `global using`	Project `<Using />` items and/or `ZGlobalUsings.cs`
Blazor `@using` in `.razor`	Nearest hierarchical `_Imports.razor`
MVC / Razor Pages `@using` in `.cshtml`	Nearest hierarchical `_ViewImports.cshtml`

Diagnostics:

ID	Severity	What it reports
GUA001	Info	Promotable C# `using` directives
GUA003	Warning	Promotable Razor `@using` directives

Visual Studio may also show its own built-in “Promote using directive to _Imports.razor”. This extension’s actions are labeled (GlobalUsingAnalyzer) so you can tell them apart. Prefer GlobalUsingAnalyzer when you care about correct multi-project ownership (e.g. Blazor Web App Client vs Server) and consistent sorted imports.

Install

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Features

GUA001 — C# usings

Reports ordinary, static, alias, and global using directives and offers code fixes to:

Move to ZGlobalUsings.cs as global using
Move to the project file as <Using />

Supports Fix All in document / project / solution (grouped by destination).

GUA003 — Razor `@using`

Reports @using lines in component / page sources (not in the hierarchical imports files themselves) and offers:

Move to nearest _Imports.razor (GlobalUsingAnalyzer) — for .razor
Move to nearest _ViewImports.cshtml (GlobalUsingAnalyzer) — for .cshtml

Behavior:

Chooses the nearest existing imports file walking up from the source folder; otherwise creates one at the project root (the folder that contains the .csproj).
Never creates _Imports.razor / _ViewImports.cshtml outside the owning project (important for multi-project Blazor Web Apps).
Skips @using values already inherited from an applicable imports file.
Sorts @using lines in the destination the same way C# <Using /> sorting works.
On .razor / .cshtml, the lightbulb entry comes from a VSIX suggested-action (C# code fixes alone cannot appear in the Razor language lightbulb).

Usage

C# (`.cs`)

Place the caret on a using that shows GUA001 (or open the lightbulb / Error List).
Choose Move to ZGlobalUsings.cs… or Move to .csproj as <Using />.
Optionally use Fix all for the chosen destination.

Razor (`.razor` / `.cshtml`)

Place the caret on an @using line (for example in Counter.razor).
Open the lightbulb (Ctrl+.).
Choose Move to nearest _Imports.razor (GlobalUsingAnalyzer)
(or _ViewImports.cshtml for MVC pages).

You can also apply fixes from the Error List when GUA003 is listed (filter Build + IntelliSense, include Warnings).

GlobalUsingAnalyzer

Install