How to get a registry value to a variable using Powershell? (implementing programmatical way to toggle dark mode in Windows 10)

Question

I'm implementing dark mode switcher for Windows 10. I've found that one can enable dark mode via

Set-ItemProperty -Path HKCU:\SOFTWARE\Microsoft\Windows\CurrentVersion\Themes\Personalize -Name AppsUseLightTheme -Value 0 -Type Dword -Force

and light mode via

Set-ItemProperty -Path HKCU:\SOFTWARE\Microsoft\Windows\CurrentVersion\Themes\Personalize -Name AppsUseLightTheme -Value 1 -Type Dword -Force

Now I want to implement toggling. I've tried

Get-ItemProperty -Path HKCU:\SOFTWARE\Microsoft\Windows\CurrentVersion\Themes\Personalize -Name AppsUseLightTheme

and instead of getting 0 or 1, got output like this:

AppsUseLightTheme : 1
PSPath            : Microsoft.PowerShell.Core\Registry::HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Themes\Personalize
PSParentPath      : Microsoft.PowerShell.Core\Registry::HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Themes
PSChildName       : Personalize
PSDrive           : HKCU
PSProvider        : Microsoft.PowerShell.Core\Registry

How do I actually get 1 to save it in a variable and do the toggling?

Answer 1

Ok, it was actually simple, had to grab the field value using dot notation:

$mode = (Get-ItemProperty -Path HKCU:\SOFTWARE\Microsoft\Windows\CurrentVersion\Themes\Personalize -Name AppsUseLightTheme).AppsUseLightTheme
$newMode = 1 - $mode
Set-ItemProperty -Path HKCU:\SOFTWARE\Microsoft\Windows\CurrentVersion\Themes\Personalize -Name AppsUseLightTheme -Value $newMode -Type Dword -Force

And here's an AutoHotKey script to toggle Dark Mode on Win+Q:

; AutoHotkey Version: 1.x
; Language:       English
; Platform:       Win9x/NT
; Author:         Yakov Litvin
; Source:         https://superuser.com/a/1724237/576393
;
; Script Function:
;   toggle Windows dark mode on Win + Q
;
; based on https://stackoverflow.com/a/35844524/3995261

psScript =
(
  $mode = (Get-ItemProperty -Path HKCU:\SOFTWARE\Microsoft\Windows\CurrentVersion\Themes\Personalize -Name AppsUseLightTheme).AppsUseLightTheme
  $newMode = 1 - $mode
  Set-ItemProperty -Path HKCU:\SOFTWARE\Microsoft\Windows\CurrentVersion\Themes\Personalize -Name AppsUseLightTheme -Value $newMode -Type Dword -Force
)

#vk51::Run, PowerShell.exe -Command &{%psScript%},, hide

#NoEnv  ; Recommended for performance and compatibility with future AutoHotkey releases.
SendMode Input  ; Recommended for new scripts due to its superior speed and reliability.
SetWorkingDir %A_ScriptDir%  ; Ensures a consistent starting directory.