	Name	Description
	PullNotificationQueueCapacity	Capacity of the event pull queue for notifications.
	SupportedTechnologies	Gets the OPC technologies supported.

	Name	Description
	AcknowledgeCondition	Acknowledges a condition in the Event Server. The client will receive event notifications (indicating the acknowledgement) from conditions. This method specifically acknowledges the condition becoming active or transitioning into a different sub-condition (and no other state transition of the condition). One or more conditions belong to a specific event source - the source of the event notification. For each condition-related event notification, the corresponding Source, Condition Name, Active Time and Cookie is received by the client as part of the event notification. Uses server descriptor for specifying the OPC server. Pass in acknowledger ID and comment.
	BrowseNodes	Browses the specified area (or root) in OPC server's process area space, and returns information about child nodes (areas or sources) found. Uses server descriptor for specifying the OPC server. A parent area descriptor is passed in. No vendor-specific filtering.
	BrowseServers	Browses the specified computer and returns information about OPC (Alarms and Events) servers found.
	ChangeEventSubscription	Changes parameters of a particular event subscription. Changes parameters of an event subscription. Specify new notification rate, subscription filter object, and an "active" flag.
	GetConditionState	Returns the current state information for the condition instance corresponding to the source and condition name, passing in a server descriptor. Also allows to retrieve specified event attributes.
	GetEventsSubscriptionArguments	Obtains parameters of specified events subscription.
	GetService	Gets the service object of the specified type. (Inherited from System.IServiceProvider)
	IsKnownEventsSubscriptionHandle	Determines whether the given event subscription handle is known to this client.
	PullMultipleNotifications	Attempts to pull multiple OPC events subscribed to by the SubscribeEvents method. Returns refresh or standard event notifications.
	QueryEventCategories	Finds out events categories supported by the server. The QueryEventCategories method gives clients a means of finding out the specific categories of events supported by a given server. This method would typically be invoked prior to specifying an event filter. Servers are able to define their own custom event categories, but a list of recommended categories is provided in the OPC specification. Server descriptor is used for specifying the OPC server. Queries event categories for given event types.
	QuerySourceConditions	Finds out event conditions associated with the specified source name. Uses server descriptor for specifying the OPC server.
	RefreshEventSubscription	Force a refresh for all active conditions and inactive, unacknowledged conditions whose event notifications match the filter of the event subscription. Clients often need to get the current condition information from the server, particularly at client startup, for things such as a current alarm summary. The OPC Event Server supports this requirement by resending the most recent event notifications which satisfy the filter in the event subscription and which are related to active and/or unacknowledged conditions. The client can then derive the current condition status from the "refreshed" event notifications.
	SubscribeEvents	Subscribe to particular OPC events. The Notification is generated for each event. Subscribe to particular OPC events, using an object that holds all necessary arguments.
	UnsubscribeAllEvents	Unsubscribe from changes of all OPC events.
	UnsubscribeEvents	Unsubscribe from particular OPC event notifications.

	Name	Description
	AcknowledgeCondition	Overloaded. Acknowledges a condition in the Event Server. The client will receive event notifications (indicating the acknowledgement) from conditions. This method specifically acknowledges the condition becoming active or transitioning into a different sub-condition (and no other state transition of the condition). One or more conditions belong to a specific event source - the source of the event notification. For each condition-related event notification, the corresponding Source, Condition Name, Active Time and Cookie is received by the client as part of the event notification. The client is required to pass the activeTime and cookie received in the event notification to the AcknowledgeCondition method without modification. The server(s) can be local or can be remotely accessed via DCOM.
	AcknowledgeMultipleConditions	Acknowledges multiple conditions in the Event Server.
	BrowseAreas	Overloaded. Browses the specified area (or root) in OPC server's process area space, and returns information about child areas found.
	BrowseNodes	Overloaded. Browses the specified area (or root) in OPC server's process area space, and returns information about child nodes (areas or sources) found.
	BrowseOne	Browses the nodes in OPC A&E server's address space. Starts from the specified node, and returns information about child nodes found. Browses the nodes in server's address space, given a browse arguments object.
	BrowseServers	Overloaded. Browses for OPC (Alarms&Events) servers.
	BrowseSources	Overloaded. Browses the specified area (or root) in OPC server's process area space, and returns information about child sources found.
	BrowseTree	Overloaded. Allows to traverse through OPC A&E address space nodes under the specified node, using given browse arguments.
	ChangeEventSubscription	Overloaded. Changes parameters of a particular event subscription.
	FindEventCategory	Attempts to find a specified event category in the OPC server, and returns information about it when found.
	FindEventCondition	Attempts to find a specified event condition in the OPC server and for given event category, and returns information about it when found.
	GetConditionState	Overloaded. Returns the current state information for the condition instance corresponding to the source and condition name. Some servers may not maintain sufficient condition state information to fully implement this method. The server(s) can be local or can be remotely accessed via DCOM.
	PullNotification	Attempts to pull an OPC event subscribed to by the SubscribeEvents method. Returns refresh or standard event notifications.
	QueryCategoryAttributes	Overloaded. Finds out event attributes that the server can provide as part of an event notification within a given event category. Uses server descriptor for specifying the OPC server.
	QueryCategoryConditions	Overloaded. Finds out event conditions supported by given event category. Uses server descriptor for specifying the OPC server.
	QueryEventCategories	Overloaded. The QueryEventCategories method gives clients a means of finding out the specific categories of events supported by a given server. This method would typically be invoked prior to specifying an event filter. Servers are able to define their own custom event categories, but a list of recommended categories is provided in the OPC specification.
	QuerySourceConditions	Finds out event conditions associated with the specified source name. Computer name and server class are used for specifying the OPC server.
	SubscribeEvents	Overloaded. Subscribe to particular OPC events. The Notification is generated for each event.
	SubscribeMultipleEvents	Overloaded. Subscribe to multiple OPC events. The size of the input array will become the size of the output array. The element positions (indices) in the output array are the same as in the input array. The function returns an array of integer handles. Each such handle uniquely identifies the events subscription. The indices of elements in the output array are the same as those in the input array.
	SupportsTechnology	Determines whether the client object supports a given OPC technology or technologies (such as OPC COM or OPC XML).
	UnsubscribeMultipleEvents	Unsubscribe from changes of multiple OPC events. Unsubscribe from changes of multiple OPC events, specifying array of integer handles.

	Name	Description
	EventingFailure	Raised when a failure in the eventing infrastructure occurs.
	Notification	Raised for every OPC event subscribed to by the SubscribeEvents method. This method can be called whether this is a refresh or standard event notification.

Reference