Can this be made to work on a remote computer? - powershell

Question

I've been killing myself trying to get this to work on a remote computer, is it even possible? If so, can someone point me in the right direction?
Here's the code:
Function Lock-WorkStation {
#Requires -Version 2.0
$signature = #"
[DllImport("user32.dll", SetLastError = true)]
public static extern bool LockWorkStation();
"#
$LockWorkStation = Add-Type -memberDefinition $signature -name "Win32LockWorkStation" -namespace Win32Functions -passthru
$LockWorkStation::LockWorkStation() | Out-Null
}

Answer 1

I can't test here, but for me it can NOT work because, as you can read in Microsoft documentation, the LockWorkStation function is callable only by processes running on the interactive desktop. In addition, the user must be logged on.
So when you connect to a remote computer using PSSession as far as I understand you are not in the interactive session.

Answer 2

Nothing to do with this, but it can help in Windows Vista/7 2008/R2, you can use the command tsdiscon.exe to lock a Remote Desktop session or your workstation.
Here is a sample where, logged as adminstrator domain on my computer, I first list, then lock the console session on my server.
PS> query session /server:WM2008R2ENT
SESSION UTILISATEUR ID ÉTAT TYPE PÉRIPHÉRIQUE
services 0 Déco
console jpb 2 Actif
PS> tsdiscon 2 /server:WM2008R2ENT

Answer 3

It's possible. But you need a workaround to connect to the interactive session.
Download the PowerShellPack and install it. You only need one module called "TaskScheduler".
I've tested the following code:
Function Lock-Workstation
{
param(
$Computername,
$Credential
)
if(!(get-module taskscheduler)){Import-Module TaskScheduler}
New-task -ComputerName $Computername -credential:$Credential |
Add-TaskTrigger -In (New-TimeSpan -Seconds 30) |
Add-TaskAction -Script `
{
$signature = #"
[DllImport("user32.dll", SetLastError = true)]
public static extern bool LockWorkStation();
"#
$LockWorkStation = Add-Type -memberDefinition $signature `
-name "Win32LockWorkStation" `
-namespace Win32Functions `
-passthru
$LockWorkStation::LockWorkStation() | Out-Null
} | Register-ScheduledTask TestTask -ComputerName $Computername `
-credential:$Credential
}
You can use it like this:
Lock-Workstation "NameOfTheComputer" (Get-Credential)
or like this:
Lock-Workstation "NameOfTheComputer"
If you receive an error in Connect-ToTaskScheduler when specifying a credential, it's because there is a typo in the module (edit Connect-ToTaskScheduler.ps1 and replace "$NetworkCredentail.Domain," with "$NetworkCredential.Domain,"