Using powershell wait-process concurrently

Question

I'm new to powershell and while practicing the examples for loops, I came across a problem that I couldn't solve.

I want to call a notification about the status of a process running in the system through a loop However, in the code, only the alarm of the process executed first among Taskmgr or Calculator is called by Wait-Process.

I mean, Wait-Process by Sequential Execution makes notification invocation by loop no longer possible

below is my code

do{
        Start-Sleep -s 3
    $Calculator = Get-Process -Name 'Calculator'
    $Taskmgr = Get-Process -Name 'Taskmgr'

    if ($Calculator)
    {
        Show-Notification -ToastTitle 'Calculator is open.'
        Wait-Process -name 'Calculator'
        Show-Notification -ToastTitle 'Calculator is closed.'
    }
    if ($Taskmgr)
    {
        Show-Notification -ToastTitle 'Taskmgr is open.'
        Wait-Process -name 'Taskmgr'
        Show-Notification -ToastTitle 'Taskmgr is closed.'
    }
} while (1 -eq 1)

Since I am Japanese, I am not familiar with English, so I am using a translator. thank you.

I'm still not good enough skill to recreate the code. sorry

I would remove the Wait-Process and just use Get-Process to check if the processes are running. Store the current state in variables (per process) and only if the state changes, send a new notification and update the state variable of that process. — zett42
– zett42, Commented Jan 27, 2023 at 22:57
I really appreciate your advice. I can't understand everything you said yet, but I will learn every single word through Google and infer the meaning of what you said. thanks! I'll help a newbie like me later :) — knight Smoke
– knight Smoke, Commented Jan 27, 2023 at 23:18

Santiago Squarzon · Accepted Answer · 2023-01-27 23:07:24Z

2

Wait-Process blocks the thread indefinitely without the -Timeout parameter but also, while using this parameter if it times out you would get an error and the cmdlet is not particularly useful for this use case.

You could achieve this by using only Get-Process with -ErrorAction SilentlyContinue to avoid errors when the processes are not running and adding else conditions:

while ($true) {
    Start-Sleep -s 3
    $calc = Get-Process -Name CalculatorApp -ErrorAction SilentlyContinue
    $taskmgr = Get-Process -Name Taskmgr -ErrorAction SilentlyContinue

    # if calc is running
    if ($calc) {
        # and there was no notification before
        if (-not $calcOpen) {
            # display notification
            'Calculator is opened.'
            # and set a reminder to not display more popups
            $calcOpen = $true
        }
    }
    # if calc was not running
    else {
        # and was running before
        if ($calcOpen) {
            # display notification
            'Calculator is closed.'
            # and set a reminder that calc has been closed
            $calcOpen = $false
        }
    }

    # same logic applies here
    if ($taskmgr) {
        if (-not $taskmgrOpen) {
            'Taskmgr is opened.'
            $taskmgrOpen = $true
        }
    }
    else {
        if ($taskmgrOpen) {
            'Taskmgr is closed.'
            $taskmgrOpen = $false
        }
    }
}

edited Jan 27, 2023 at 23:07

answered Jan 27, 2023 at 22:57

Santiago Squarzon

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3 Comments

zett42 Over a year ago

Well, that would output messages every 3 seconds, while my understanding is that OP wants to show a message only when the state changes. At least that would make sense for showing a toast notification.

knight Smoke Over a year ago

Surprisingly, it matches exactly the behavior I intended. I still don't understand how it works for this code, but I'm going to dismantle it one by one and study how it works. Thank you so much for sharing your treasured knowledge. Have a good day sir :D!!

Santiago Squarzon Over a year ago

my pleasure @knightSmoke you too have a great day sir :)

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