Wait-Event

Applies To: Windows PowerShell 2.0

Waits until a particular event is raised before continuing to run.

Syntax

Wait-Event [[-SourceIdentifier] <string>] [-Timeout <int>] [<CommonParameters>]

Description

The Wait-Event cmdlet suspends execution of a script or function until a particular event is raised. Execution resumes when the event is detected. To cancel the wait, press CTRL+C.

This feature provides an alternative to polling for an event. It also allows you to determine the response to an event in two different ways: by using the Action parameter of the event subscription and by waiting for an event to return and then respond with an action.

Parameters

-SourceIdentifier <string>

Waits only for events with the specified source identifier. By default, Wait-Events waits for any event.

-Timeout <int>

Determines the maximum time, in seconds, that Wait-Event waits for the event to occur. The default, -1, waits indefinitely. The timing starts when you submit the Wait-Event command.

If the specified time is exceeded, the wait ends and the command prompt returns, even if the event has not been raised. No error message is displayed.

<CommonParameters>

This command supports the common parameters: Verbose, Debug, ErrorAction, ErrorVariable, OutBuffer, OutVariable, WarningAction, and WarningVariable. For more information, see about_CommonParameters.

Inputs and Outputs

The input type is the type of the objects that you can pipe to the cmdlet. The return type is the type of the objects that the cmdlet returns.

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.

Example 1

C:\PS>wait-event

Description

-----------

This command waits for the next event that is raised.

Example 2

C:\PS>wait-event -sourceIdentifier "ProcessStarted"

Description

-----------

This command waits for the next event that is raised and that has a source identifier of "ProcessStarted".

Example 3

C:\PS>$timer.Interval = 2000 
C:\PS> $timer.Autoreset = $false 
C:\PS> $timer.Enabled = $true; Wait-Event Timer.Elapsed

# After 2 seconds 

EventIdentifier  : 12 
Sender           : System.Timers.Timer 
SourceEventArgs  : System.Timers.ElapsedEventArgs 
SourceArgs       : {System.Timers.Timer, System.Timers.ElapsedEventArgs} 
SourceIdentifier : Timer.Elapsed 
TimeGenerated    : 6/10/2008 3:24:18 PM 
MessageData      : 
ForwardEvent     : False

Description

-----------

This command uses the Wait-Event cmdlet to wait for a timer event on a timer that is set for 2000 milliseconds.

Example 4

C:\PS>wait-event -sourceIdentifier "ProcessStarted" -timeout 90

Description

-----------

This command waits up to 90 seconds for the next event that is raised and that has a source identifier of "ProcessStarted". If the specified time expires, the wait ends.

See Also

Concepts

Register-ObjectEvent
Register-EngineEvent
Register-WmiEvent
Unregister-Event
Get-Event
New-Event
Remove-Event
Wait-Event
Get-EventSubscriber