Exploring the Power of Get-Event in PowerShell

Welcome back to Wahmans PowerShell Blog! Today we’re diving into the Get-Event cmdlet — a neat tool in PowerShell’s toolbox that lets you retrieve events from the event queue. This can be very handy when working with event-driven scripts or responding to asynchronous events.

What is Get-Event?

According to Microsoft Docs, Get-Event “gets the events in the event queue.” Essentially, it allows us to inspect and respond to events that have been registered and triggered but not yet processed.

The event queue holds events that your script has subscribed to using cmdlets like Register-EngineEvent, Register-ObjectEvent, or Register-WmiEvent. Once an event is triggered, it gets queued and you can retrieve it using Get-Event.

Example 1: Basic Usage – Get all events in the queue

Get-Event

This command simply retrieves all the events currently in the PowerShell event queue. If there are no events, nothing will be returned.

Example 2: Registering and Retrieving a Timer Event

# Create a timer object
$timer = New-Object Timers.Timer
$timer.Interval = 1000
$timer.AutoReset = $true
$timer.Enabled = $true

# Register for the Elapsed event
Register-ObjectEvent -InputObject $timer -EventName Elapsed -SourceIdentifier TimerElapsed

# Wait a few seconds so the timer can trigger
Start-Sleep -Seconds 3

# Get the events from the queue
Get-Event

In this example, we register an event on a timer. When the timer ticks (every second), it raises an event. After sleeping, we use Get-Event to retrieve the queued timer events. This is great for learning how events are queued.

Example 3: Filtering Events by SourceIdentifier

# Get only events from the timer
Get-Event -SourceIdentifier TimerElapsed

Sometimes you register for multiple events and you only want to inspect or handle a specific event. This command filters the event queue for events with the SourceIdentifier TimerElapsed.

Example 4: Programmatically Handling Events

# Handle each event and remove it from the queue
while ($event = Get-Event -SourceIdentifier TimerElapsed) {
    Write-Host "Timer ticked at: $($event.TimeGenerated)"
    Remove-Event -SourceIdentifier TimerElapsed
}

This loop demonstrates how you can process and remove events in a controlled program flow. Each time the timer ticks, the script writes the time it ticked and removes the event from the queue to prevent duplication.

Conclusion

Get-Event is a powerful cmdlet when dealing with registered events in PowerShell. It allows you to inspect, debug, and control how events are handled within your automation scripts. Whether you’re just getting started with events or you’re building robust event-driven solutions, mastering Get-Event is a great step forward.

Happy scripting, and I will see you in the next post!