Register-EngineEvent

Reference

Module:: Microsoft.PowerShell.Utility

Subscribes to events that are generated by the Windows PowerShell engine and by the New-Event cmdlet.

Syntax

Register-EngineEvent
        [-SourceIdentifier] <String>
        [[-Action] <ScriptBlock>]
        [-MessageData <PSObject>]
        [-SupportEvent]
        [-Forward]
        [-MaxTriggerCount <Int32>]
        [<CommonParameters>]

Description

The Register-EngineEvent cmdlet subscribes to events that are generated by the Windows PowerShell engine and the New-Event cmdlet. Use the SourceIdentifier parameter to specify the event.

You can use this cmdlet to subscribe to the Exiting engine event and events generated by the New-Event cmdlet. These events are automatically added to your event queue in your session without subscribing. However, subscribing lets you forward the events, specify an action to respond to the events, and cancel the subscription.

When the subscribed event is raised, it is added to the event queue in your session. To get events in the event queue, use the Get-Event cmdlet.

When you subscribe to an event, an event subscriber is added to your session. To get the event subscribers in the session, use the Get-EventSubscriber cmdlet. To cancel the subscription, use the Unregister-Event cmdlet, which deletes the event subscriber from the session.

Examples

Example 1: Register a PowerShell engine event on remote computers

PS C:\> $S = New-PSSession -ComputerName "Server01, Server02"
PS C:\> Invoke-Command -Session $S { Register-EngineEvent -SourceIdentifier ([System.Management.Automation.PsEngineEvent]::Exiting) -Forward }

This command registers for a Windows PowerShell engine event on two remote computers.

The first command creates a user-managed session (PSSession) on each of the remote computers.

The second command uses the Invoke-Command cmdlet to run the Register-EngineEvent command in the remote sessions.

The Register-EngineEvent command uses the SourceIdentifier parameter to identify the event. It uses the Forward parameter to forward the events from the remote session to the local session.

Example 2: Take a specified action when the Exiting event occurs

PS C:\> Register-EngineEvent -SourceIdentifier PowerShell.Exiting -SupportEvent -Action {
     Get-History | Export-Clixml $Home\history.clixml
}

This command shows how to run Register-EngineEvent to take a specific action when the PowerShell.Exiting event occurs. The SupportEvent parameter is added to hide the event subscription. When Windows PowerShell exits, in this case, the command history from the exiting session is exported in XML format to a file name and path in the user's $Home directory.

Parameters

-Action

Specifies commands to handle the events. The commands in the Action run when an event is raised, instead of sending the event to the event queue. Enclose the commands in braces ( { } ) to create a script block.

The value of the Action parameter can include the $Event, $EventSubscriber, $Sender, $EventArgs, and $Args automatic variables, which provide information about the event to the Action script block. For more information, see about_Automatic_Variables (https://go.microsoft.com/fwlink/?LinkID=113212).

When you specify an action, Register-EngineEvent returns an event job object that represents that action. You can use the Job cmdlets to manage the event job.

Type:	ScriptBlock
Position:	101
Default value:	None
Required:	False
Accept pipeline input:	False
Accept wildcard characters:	False

-Forward

Indicates that the cmdlet sends events for this subscription to the session on the local computer. Use this parameter when you are registering for events on a remote computer or in a remote session.

Type:	SwitchParameter
Position:	Named
Default value:	None
Required:	False
Accept pipeline input:	False
Accept wildcard characters:	False

-MaxTriggerCount

Specifies the max trigger count.

When you specify an action, Register-EngineEvent returns an event job object that represents that action. You can use the Job cmdlets to manage the event job.

Type:	Int32
Position:	Named
Default value:	None
Required:	False
Accept pipeline input:	False
Accept wildcard characters:	False

-MessageData

Specifies additional data associated with the event. The value of this parameter appears in the MessageData property of the event object.

Type:	PSObject
Position:	Named
Default value:	None
Required:	False
Accept pipeline input:	False
Accept wildcard characters:	False

-SourceIdentifier

Specifies the source identifier of the event to which you are subscribing. The source identifier must be unique in the current session. This parameter is required.

The value of this parameter appears in the value of the SourceIdentifier property of the subscriber object and of all event objects associated with this subscription.

Supported EngineEvent values include PowerShell.Exiting, PowerShell.OnIdle, and PowerShell.OnScriptBlockInvoke.

Type:	String
Position:	100
Default value:	None
Required:	True
Accept pipeline input:	False
Accept wildcard characters:	False

-SupportEvent

Indicates that the cmdlet hides the event subscription. Add this parameter when the current subscription is part of a more complex event registration mechanism and it should not be discovered independently.

To view or cancel a subscription that was created with the SupportEvent parameter, add the Force parameter to the Get-EventSubscriber or Unregister-Event cmdlets.

Type:	SwitchParameter
Position:	Named
Default value:	None
Required:	False
Accept pipeline input:	False
Accept wildcard characters:	False

Inputs

None

You cannot pipe input to Register-EngineEvent.

Outputs

None or System.Management.Automation.PSEventJob

If you use the Action parameter, Register-EngineEvent returns a System.Management.Automation.PSEventJob object. Otherwise, it does not generate any output.

Notes

Events, event subscriptions, and the event queue exist only in the current session. If you close the current session, the event queue is discarded and the event subscription is canceled.