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New-Event

  • Reference
Module:
Microsoft.PowerShell.Utility

Creates a new event.

Syntax

New-Event
   [-SourceIdentifier] <String>
   [[-Sender] <PSObject>]
   [[-EventArguments] <PSObject[]>]
   [[-MessageData] <PSObject>]
   [<CommonParameters>]

Description

The New-Event cmdlet creates a new custom event.

You can use custom events to notify users about state changes in your program and any change that your program can detect, including hardware or system conditions, application status, disk status, network status, or the completion of a background job.

Custom events are automatically added to the event queue in your session whenever they are raised; you do not need to subscribe to them. However, if you want to forward an event to the local session or specify an action to respond to the event, use the Register-EngineEvent cmdlet to subscribe to the custom event.

When you subscribe to a custom event, the event subscriber is added to your session. If you cancel the event subscription by using the Unregister-Event cmdlet, the event subscriber and custom event are deleted from the session. If you do not subscribe to the custom event, to delete the event, you must change the program conditions or close the PowerShell session.

Examples

Example 1: Create a new event in the event queue

PS C:\> New-Event -SourceIdentifier Timer -Sender windows.timer -MessageData "Test"

This command creates a new event in the PowerShell event queue. It uses a Windows.Timer object to send the event.

Example 2: Raise an event in response to another event

PS C:\> function Enable-ProcessCreationEvent
{
   $Query = New-Object System.Management.WqlEventQuery "__InstanceCreationEvent", (New-Object TimeSpan 0,0,1), "TargetInstance isa 'Win32_Process'"
   $ProcessWatcher = New-Object System.Management.ManagementEventWatcher $Query
   $Identifier = "WMI.ProcessCreated"
   Register-ObjectEvent $ProcessWatcher "EventArrived" -SupportEvent $Identifier -Action
   {
      [void] (New-Event -SourceID "PowerShell.ProcessCreated" -Sender $Args[0] -EventArguments $Args[1].SourceEventArgs.NewEvent.TargetInstance)
   }
}

This sample function uses the New-Event cmdlet to raise an event in response to another event. The command uses the Register-ObjectEvent cmdlet to subscribe to the Windows Management Instrumentation (WMI) event that is raised when a new process is created. The command uses the Action parameter of the cmdlet to call the New-Event cmdlet, which creates the new event.

Because the events that New-Event raises are automatically added to the PowerShell event queue, you do not need to register for that event.

Parameters

-EventArguments

Specifies an object that contains options for the event.

Type:PSObject[]
Position:2
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:3
Default value:None
Required:False
Accept pipeline input:False
Accept wildcard characters:False

-Sender

Specifies the object that raises the event. The default is the PowerShell engine.

Type:PSObject
Position:1
Default value:None
Required:False
Accept pipeline input:False
Accept wildcard characters:False

-SourceIdentifier

Specifies a name for the new event. This parameter is required, and it must be unique in the session.

The value of this parameter appears in the SourceIdentifier property of the events.

Type:String
Position:0
Default value:None
Required:True
Accept pipeline input:False
Accept wildcard characters:False

Inputs

None

You cannot pipe input to this cmdlet.

Outputs

PSEventArgs

Notes

No event sources available on the Linux or macOS platforms.

The new custom event, the event subscription, 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.