| | Name | Description |
|---|
 | AckRequired | Only for Condition events. This flag indicates that the related condition requires acknowledgment of this event. The determination of those events which require acknowledgment is server specific. For example, transition into a LimitAlarm condition would likely require an acknowledgment, while the event notification of the resulting acknowledgment would likely not require an acknowledgment. |
| ActiveTime | Time that the condition became active (for single-state conditions), or the time of the transition into the current sub-condition (for multi-state conditions). This time is used by the client when acknowledging the condition (see EventServer.AckCondition method). |
| ActorID | Only for Tracking events. For tracking events, this is the actor ID for the event notification. For condition-related events, this is the AcknowledgerID when OPC_CONDITION_ACKED is set in wNewState. If the AcknowledgerID is a NULL string, the event was automatically acknowledged by the server. For other events, the value is null (Nothing). |
| ChangeMask | Only for Condition events. Indicates to the client which properties of the condition have changed, to have caused the server to send the event notification. It may have one or more of the EventChangeMask enumerator values. If the event notification is the result of a Refresh, these bits are to be ignored. For a 'new event', EventChangeMask.ActivState is the only bit which will always be set. Other values are server specific. (A 'new event' is any event resulting from the related condition leaving the Inactive and Acknowledged state.) |
| ConditionName | Only for Condition events. The name of the condition related to this event notification. |
| Cookie | Only for Condition events. Server defined cookie associated with the event notification. This value is used by the client when acknowledging the condition (see AckCondition method). This value is opaque to the client. |
| EventAttributes | Array of vendor specific event attributes returned for this event notification. See the EventSubscription.SelectReturnedAttributes method. The order of the items returned matches the order that was specified by the select. |
| EventCategory | Standard and Vendor-specific event category codes. |
| EventType | A value of the EventType enumerator for Simple, Condition-Related, or Tracking events, respectively. |
| Message | Event notification message describing the event. |
| NewState | Only for Condition events. A bit mask of ConditionState enumerator values specifying the new state of the condition. See OPC spec section 2.4.9 and Figure 2-2 for exactly which state transitions generate event notifications. |
| NumEventAttrs | The length of the vendor specific event attribute array. |
| Quality | Only for Condition events. Quality associated with the condition state. Values are as defined for the OPC Quality Flags in the OPC Data Access Server specification. |
| Severity | Event severity (1..1000). |
| Source | The source of event notification. This Source can be used in the TranslateToItemIDs method to determine any related OPC Data Access itemIDs. |
| SubconditionName | Only for Condition events. The name of the current sub-condition, for multi-state conditions. For a single-state condition, this contains the condition name. |
| Time | Time of the event occurrence - for conditions, time that the condition transitioned into the new state or sub-condition. For example, if the event notification is for acknowledgment of a condition, this would be the time that the condition became acknowledged. |
Public Constructors