PowerShell - how to stop script processing elapsed events from Timer class

Question

I'm writing a PowerShell script in Visual Studio Code which is intended to run a function for every tick of a timer. Here is the code:

$timer = New-Object Timers.Timer
$timer.Interval = 1000
$timer.Enabled = $true

Register-ObjectEvent -InputObject $timer -EventName Elapsed -Action {Write-Host "Tick"}

The problem is that I don't seem to be able to stop the script using Ctrl+C which is what I would normally do, or indeed anything other than actually killing the terminal using the 'dustbin' icon. It just continues printing 'Tick'!

What's going on here? How would I stop this script gracefully?

Get-EventSubscriber |Unregister-Event

Mathias R. Jessen
– Mathias R. Jessen

2021-02-11 13:24:57 +00:00
Commented Feb 11, 2021 at 13:24 — Mathias R. Jessen
– Mathias R. Jessen, Commented Feb 11, 2021 at 13:24

Mathias R. Jessen · Accepted Answer · 2021-02-11 13:29:50Z

1

When you subscribe an action to an event using Register-ObjectEvent, it can be unregistered using the Unregister-Event cmdlet:

$timer = New-Object Timers.Timer
$timer.Interval = 1000
$timer.Enabled = $true

Register-ObjectEvent -SourceIdentifier MyElapsedTick -InputObject $timer -EventName Elapsed -Action {Write-Host "Tick"}

<# ... #>

Unregister-Event -SourceIdentifier MyElapsedTick

To enumerate existing subscribers (for when you forget to specify a SourceIdenfitier for example), use Get-EventSubscriber:

# This will unregister all event subscribers
Get-EventSubscriber |Unregister-Event

answered Feb 11, 2021 at 13:29

Mathias R. Jessen

178k13 gold badges175 silver badges234 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

David Over a year ago

My question is not so much about how to unregister, more how to stop the script. So I need the script to know I'm trying to stop it, so that it can unregister... :)

Mathias R. Jessen Over a year ago

@David I don't understand what you mean by "stop the script". The script/snippet you posted stops running as soon as Register-ObjectEvent returns, but the event subscription will persist until you unregister (or terminate the process)

David Over a year ago

Okay, thank you, I understand now. The event registration is independent of the script. So Ctrl+D does stop the script (or would do, if the script hadn't already stopped after calling Register-ObjectEvent, as you say), but the events keep on ticking away.

David Over a year ago

What I didn't realise from your original post (my fault, not yours) is that I can call Unregister-Event -SourceIdentifier MyElapsedTick outside of the script and it would still work. I assumed that the event registration would be scoped to the script, but that's clearly not the case.

Алексей Семенов · Accepted Answer · 2021-02-11 13:48:32Z

1

$timer = [System.Timers.Timer]::new()
$timer.Interval = 5000
$timer.AutoReset = $false
$timer.Enabled = $true
1..20 | % {
    if (!$timer.Enabled){
        exit
    }
    write-host $_, $timer.Enabled
    Start-Sleep -Milliseconds 1000
}

answered Feb 11, 2021 at 13:48

Алексей Семенов

8565 silver badges11 bronze badges

4 Comments

Mark Rotteveel Over a year ago

Please don't post only code as answer, but also provide an explanation what your code does and how it solves the problem of the question. Answers with an explanation are usually more helpful and of better quality, and are more likely to attract upvotes.

Алексей Семенов Over a year ago

I'am russian, i can read in English, but write in English it is hard for me.

NKSM Over a year ago

@АлексейСеменов, You can always use Google translator or another translator. Your comment is well written.

David Over a year ago

@АлексейСеменов I very much appreciate your help, thank you!

Collectives™ on Stack Overflow

PowerShell - how to stop script processing elapsed events from Timer class

2 Answers 2

4 Comments

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

4 Comments

4 Comments

Your Answer

Sign up or log in

Post as a guest

Related