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Wait-Event

  • Reference
Module:
Microsoft.PowerShell.Utility

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

Syntax

Wait-Event
    [[-SourceIdentifier] <String>]
    [-Timeout <Int32>]
    [<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.

Examples

Example 1: Wait for the next event

PS C:\> Wait-Event

This command waits for the next event that is raised.

Example 2: Wait for an event with a specified source identifier

PS C:\> Wait-Event -SourceIdentifier "ProcessStarted"

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

Example 3: Wait for a timer elapsed event

PS C:\> $Timer.Interval = 2000
PS C:\> $Timer.Autoreset = $False
PS C:\> $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

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

Example 4: Wait for an event after a specified timeout

PS C:\> Wait-Event -SourceIdentifier "ProcessStarted" -Timeout 90

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.

Parameters

-SourceIdentifier

Specifies the source identifier that this cmdlet waits for events. By default, Wait-Event waits for any event.

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

-Timeout

Specifies 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.

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

Inputs

String

Outputs

PSEventArgs

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.