powershell - 在 Powershell 中设置后机器级环境变量不可用

Question

以下代码未按预期返回“Y”。仅在下一个 session (另一个新窗口)中才有效？我希望它立即可用？

    [Environment]::SetEnvironmentVariable("X", "Y", "Machine")
    Write-Host $env:X

Answer 1

您必须这样做，因为进程在启动时获取环境变量，而不是在运行时获取环境变量(即您必须重新启动 shell 才能使其按您的方式工作):

 [Environment]::SetEnvironmentVariable("X", "Y", "Machine")
 $Env:X = "Y"

还有一种方法可以使用 WM_SETTINGCHANGE 将其广播到其他窗口

To effect a change in the environment variables for the system or the user, broadcast this message with lParam set to the string "Environment".)

# Notify system of change via WM_SETTINGCHANGE
    if (! ("Win32.NativeMethods" -as [Type]))
    {
        Add-Type -Namespace Win32 -Name NativeMethods -MemberDefinition @"
            [DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
            public static extern IntPtr SendMessageTimeout( IntPtr hWnd, uint Msg, UIntPtr wParam, string lParam, uint fuFlags, uint uTimeout, out UIntPtr lpdwResult);
"@
    }

    $HWND_BROADCAST = [IntPtr] 0xffff; $WM_SETTINGCHANGE = 0x1a; $result = [UIntPtr]::Zero
    [Win32.Nativemethods]::SendMessageTimeout($HWND_BROADCAST, $WM_SETTINGCHANGE, [UIntPtr]::Zero, "Environment", 2, 5000, [ref] $result) | out-null
}