# OpcMonitoredItem Members

> Reference: Provides information about a node and its attribute being monitored by a dedicated OpcSession.

<dl class="api-definition">
<dt>Type</dt>
<dd><a href="./">OpcMonitoredItem</a></dd>
<dt>Namespace</dt>
<dd><a href="../namespaces/opc.uafx.server">Opc.UaFx.Server</a></dd>
<dt>Assembly</dt>
<dd>Opc.UaFx.Advanced.dll</dd>
<dt>Package</dt>
<dd>Opc.UaFx.Advanced v2.59.0</dd>
</dl>

## Properties

### Attribute

Gets a value indicating which [OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/) is monitored.

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

```csharp
public OpcAttribute Attribute { get; }
```

</div>

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

```vbnet
Public ReadOnly Property Attribute As OpcAttribute
```

</div>

**Property value**

[OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/)

One of the members defined by the [OpcAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/) enumeration.

### Filter

Gets the filter used to restrict the information observed and published to the client which owns the [Session](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcmonitoreditem/members#session).

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

```csharp
public OpcMonitoringFilter Filter { get; }
```

</div>

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

```vbnet
Public ReadOnly Property Filter As OpcMonitoringFilter
```

</div>

**Property value**

[OpcMonitoringFilter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcmonitoringfilter/)

An instance of the [OpcMonitoringFilter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcmonitoringfilter/) class which can also be a [OpcDataChangeFilter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatachangefilter/) in case of data changes are monitored or a [OpcEventFilter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opceventfilter/) in case of event notifications are monitored by the item.

### IsMonitoringEnabled

Gets a value indicating whether the [Attribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcmonitoreditem/members#attribute) of the node identified by [NodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcmonitoreditem/members#nodeid) is being observed.

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

```csharp
public bool IsMonitoringEnabled { get; }
```

</div>

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

```vbnet
Public ReadOnly Property IsMonitoringEnabled As Boolean
```

</div>

**Property value**

[Boolean](https://learn.microsoft.com/dotnet/api/system.boolean)

The value true if the item is currenly being monitored; otherwise the value false.

### Mode

Gets a value which specifies how the monitoring of the [Attribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcmonitoreditem/members#attribute) of the node identified by [NodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcmonitoreditem/members#nodeid) is observed.

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

```csharp
public OpcMonitoringMode Mode { get; }
```

</div>

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

```vbnet
Public ReadOnly Property Mode As OpcMonitoringMode
```

</div>

**Property value**

[OpcMonitoringMode](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcmonitoringmode/)

One of the members defined by the [OpcMonitoringMode](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcmonitoringmode/) enumeration.

### NodeId

Gets the node identifier of the [IOpcNode](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.iopcnode/) being monitored.

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

```csharp
public OpcNodeId NodeId { get; }
```

</div>

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

```vbnet
Public ReadOnly Property NodeId As OpcNodeId
```

</div>

**Property value**

[OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/)

An instance of the [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) class.

### QueueSize

Gets the upper limit of the queue used to store observation results.

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

```csharp
public long QueueSize { get; }
```

</div>

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

```vbnet
Public ReadOnly Property QueueSize As Long
```

</div>

**Property value**

[Int64](https://learn.microsoft.com/dotnet/api/system.int64)

The upper limit of the queue used. In case there the queue reaches the size used, it will discard the oldest entry before a new one is enqueued.

### SamplingInterval

Gets a value indicating the interval used to sample the value of the attribute of the node in milliseconds.

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

```csharp
public double SamplingInterval { get; }
```

</div>

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

```vbnet
Public ReadOnly Property SamplingInterval As Double
```

</div>

**Property value**

[Double](https://learn.microsoft.com/dotnet/api/system.double)

The milliseconds used as the interval used for observation.

### Session

Gets the session which owns this [OpcMonitoredItem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcmonitoreditem/).

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

```csharp
public OpcSession Session { get; }
```

</div>

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

```vbnet
Public ReadOnly Property Session As OpcSession
```

</div>

**Property value**

[OpcSession](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcsession/)

An instance of the [OpcSession](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcsession/) class which owns this monitored item.