Environment Variables

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Overview

Environment Variables is a PowerToys module that provides an easy and convenient way to manage Windows environment variables. It offers a modern user interface for viewing, editing, and managing both user and system environment variables.

Features

View and edit user and system environment variables in a unified interface
Create profiles to group and manage sets of variables together
Profile-based variable management with on/off toggles
Automatic backup of existing variables when overridden by a profile
Restoration of original values when profiles are disabled

How It Works

Profiles

Profiles are collections of environment variables that can be enabled or disabled together. When a profile is enabled:

Variables in the profile override existing User variables with the same name
Original values are automatically backed up for restoration when the profile is disabled
Only one profile can be active at a time

Variable Precedence

The module follows this precedence order for environment variables:

Active profile variables (highest precedence)
User variables
System variables (lowest precedence)

Architecture

The Environment Variables module is structured into three main components:

Project Structure

EnvironmentVariables/               # Contains assets, main windows, and telemetry
EnvironmentVariablesModuleInterface # Interface definitions and package configurations
EnvironmentVariableUILib            # Abstracted UI methods and implementations

Key Components

Main Window Framework: Builds the modern Windows desktop UI, handles Windows messages, resource loading, and window closing operations
Project Configuration: Defines settings and configurations for the module
UI Implementation: Contains the user interface components and the backend logic

Implementation Details

Key Functions

OpenEnvironmentKeyIfExists: Accesses environment information through registry keys
SetEnvironmentVariableFromRegistryWithoutNotify: Sets variables directly to registry instead of using Environment API, avoiding the 1-second timeout for settings change notifications
GetVariables: Reads variables directly from registry instead of using Environment API to prevent automatic variable expansion

Technical Notes

The module reads and writes variables directly to the registry instead of using the Environment API
This direct registry access approach is used because the Environment API automatically expands variables and has a timeout for notifications
When a profile variable has the same name as an existing User variable, a backup is created with a naming pattern: VARIABLE_NAME_powertoys_PROFILE_NAME

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