__InstanceModificationEvent class

The __InstanceModificationEvent system class reports an instance modification event, which is a type of intrinsic event generated when an instance changes in the namespace.

The following syntax is simplified from Managed Object Format (MOF) code and includes all inherited properties. Properties are listed in alphabetic order, not MOF order.


class __InstanceModificationEvent : __InstanceOperationEvent
  object PreviousInstance;
  object TargetInstance;
  uint64 TIME_CREATED;


The __InstanceModificationEvent class has these types of members:


The __InstanceModificationEvent class has these properties.


Data type: object

Access type: Read-only

Copy of the instance prior to modification.


Data type: uint8 array

Access type: Read-only

Descriptor used by the event provider to determine which users can receive the event. This property is inherited from __Event.


Data type: object

Access type: Read-only

New version of the changed instance. This property is inherited from __InstanceOperationEvent.


Data type: uint64

Access type: Read-only

Unique value that indicates the time at which the event was generated. This is a 64-bit value that represents the number of 100-nanosecond intervals after January 1, 1601. The information is in the Coordinated Universal Times (UTC) format. This property is inherited from __Event.

For more information about using uint64 values in scripts, see Scripting in WMI.


The __InstanceModificationEvent class is derived from __InstanceOperationEvent.

Modification of a resource: __InstanceModificationEvent

Suppose you suspect that a management application you are using is erroneously changing the startup type of a service on one of your servers. You want to write a WMI script to monitor any modifications made to the configuration of the service. As soon as a modification is made to a service, its corresponding TargetInstance reflects the modification.

If you register your interest in this event, a modification to the configuration of the service results in the creation of an instance of the __InstanceModificationEvent class.

Notification queries that request notification of the modification of a resource and use intrinsic events all use syntax similar to the following:

SELECT * FROM __InstanceModificationEvent WITHIN PollingInterval WHERE TargetInstance ISA 'Win32_Service' and TargetInstance.Name = 'alerter'


Requirement Value
Minimum supported client
Windows Vista
Minimum supported server
Windows Server 2008
All WMI namespaces

See also


WMI System Classes