# OpcMonitoredItem Class

<dl class="api-definition">
<dt>Namespace</dt>
<dd><a href="../namespaces/opc.uafx.client">Opc.UaFx.Client</a></dd>
<dt>Assembly</dt>
<dd>Opc.UaFx.Advanced.dll</dd>
<dt>Package</dt>
<dd>Opc.UaFx.Advanced v2.59.0</dd>
<dt>Members</dt>
<dd><a href="./members">OpcMonitoredItem Members</a></dd>
<dt>Also in</dt>
<dd>Opc.UaFx.Client</dd>
</dl>

Represents a node and one of its attributes (= node data) to subscribe to monitor data changes or events on the node.

## Syntax

<div class="api-signature" data-lang="csharp">

```csharp
public class OpcMonitoredItem
```

</div>

<div class="api-signature" data-lang="vbnet">

```vbnet
Public Class OpcMonitoredItem
```

</div>

## Inheritance

[Object](https://learn.microsoft.com/dotnet/api/system.object) → **OpcMonitoredItem**

## Constructors

| Name | Description |
|---|---|
| [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#opcmonitoreditem)<span class="api-meta">2 overloads</span> | Initializes a new instance of the OpcMonitoredItem class using the `nodeId` and `attribute` specified. |

## Properties

| Name | Description |
|---|---|
| [Attribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#attribute) | Gets or sets the [OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/) to monitor. |
| [CacheQueueSize](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#cachequeuesize) | Gets or sets the total number of notifications which can be queued in the OpcMonitoredItem related notification cache. |
| [ClientID](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#clientid) | Gets the client-assigned unique identifier for this OpcMonitoredItem. |
| [DisplayName](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#displayname) | Gets or sets the name of the OpcMonitoredItem used just for display purpose in the client application. |
| [Encoding](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#encoding) | Gets or sets the name of the data encoding to use. |
| [Filter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#filter) | Gets or sets the filter to evaluate while generating notifications for this OpcMonitoredItem. |
| [IndexRange](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#indexrange) | Gets or sets the range of array indeces to monitor. |
| [IsCreated](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#iscreated) | Gets a value indicating whether this OpcMonitoredItem has been created on the server. |
| [IsModified](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#ismodified) | Gets a value indicating whether this OpcMonitoredItem has been modified since it has been created on the server or since its previous changes has been committed to the server. |
| [LastDataChange](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#lastdatachange) | Gets the last data change-related notification data received from the server. |
| [LastEvent](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#lastevent) | Gets the last event-related notification data received from the server. |
| [LastNotification](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#lastnotification) | Gets the last notification received from the server. |
| [MonitoringMode](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#monitoringmode) | Gets or sets the monitoring mode which applies to the monitored item. |
| [NodeCategory](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#nodecategory) | Gets or sets the kind of node to monitor. |
| [NodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#nodeid) | Gets or sets the node identifier of the node to monitor. |
| [QueueMode](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#queuemode)<span class="api-meta">since v2.7</span> | Gets or sets the mode used to enqueue and dequeue notification data items. |
| [QueueSize](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#queuesize) | Gets or sets a value which defines the requested total number of notifications the server shall queue for this OpcMonitoredItem. |
| [RelativePath](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#relativepath) | Gets or sets the relative path to the node to monitor starting at the node identified by the [NodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#nodeid). |
| [ResolvedNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#resolvednodeid) | Gets the resolved node identifier of the node to monitor. |
| [SamplingInterval](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#samplinginterval) | Gets or sets the requested number of milliseconds of the interval within the server have to access and evaluate this OpcMonitoredItem. |
| [Status](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#status) | Gets the status information which defines the servers ability to define/provide a monitored item configured like this OpcMonitoredItem. |
| [Subscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#subscription) | Gets the [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/) this OpcMonitoredItem belongs to. |
| [Tag](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#tag) | Gets or sets the object that contains additional user data about the monitored item. |

## Methods

| Name | Description |
|---|---|
| [OnDataChangeReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#ondatachangereceived)<span class="api-meta">protected · virtual</span> | Raises the [DataChangeReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#datachangereceived) event of the OpcMonitoredItem. |
| [OnEventReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#oneventreceived)<span class="api-meta">protected · virtual</span> | Raises the [EventReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#eventreceived) event of the OpcMonitoredItem. |
| [ToString](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#tostring)<span class="api-meta">override</span> | Returns a string that represents the current OpcMonitoredItem. |

## Events

| Name | Description |
|---|---|
| [DataChangeReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#datachangereceived) | Occurs when a data change notification has been received. |
| [EventReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#eventreceived) | Occurs when an event notification has been received. |

## Applies to

| Package | Versions |
|---|---|
| Opc.UaFx.Advanced | v2.5–v2.59 |