# Events

<dl class="api-definition">
<dt>Concept</dt>
<dd><a href="/docs/development/opcua/client/events">Events</a></dd>
</dl>

| Type | Description |
|---|---|
| [OpcAlarmCondition](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcalarmcondition/) | Represents a snapshot of a 'Opc.UaFx.OpcAlarmConditionNode'. |
| [OpcClient](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/) | Provides session based methods to access OPC UA server services. |
| [OpcEvent](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcevent/) | Represents a snapshot of a 'Opc.UaFx.OpcEventNode'. |
| [OpcEventFilter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opceventfilter/) | Represents the filter of a monitored item for events, as defined by the EventFilter of OPC UA: the select clauses define the fields to report of each event and the where clause defines the events to report. |
| [OpcEventReceivedEventArgs](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opceventreceivedeventargs/) | Provides the event data for the [EventReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/eventreceived), [EventReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/members#eventreceived) and [EventReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#eventreceived) events. |
| [OpcEventSeverity](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opceventseverity/) | Defines the different indications of the urgency of an event. |
| [OpcEventTypes](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opceventtypes/) | Provides additional metadata and service routines for the different types of events supported and defined by the OPC UA Foundation Stack. |
| [OpcFilter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcfilter/) | Provides the entry point to construct filters for monitored items. |
| [OpcObjectTypes](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcobjecttypes/) | Provides the identifiers of the object types and objects defined by the OPC UA namespace and of the nodes related to them. |
| [OpcSimpleAttributeOperand](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcsimpleattributeoperand/) | Represents an operand of an [OpcContentFilterElement](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opccontentfilterelement/) which is the value of an attribute of a node described by a type definition and a path of browse names. |
| [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/) | Provides mechanisms to monitor a set of attributes (= node data) and (node-related) events using notifications being reported from the server to the client. |