# OpcObjectTypes.OpcModellingRule Members

> Reference: Represents the identifier of the ModellingRuleType object type and provides the identifiers of the nodes related to it.

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

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

## Properties

### ExposesItsArray

Gets the identifier of the ModellingRule\_ExposesItsArray object.

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

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

</div>

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

```vbnet
Public ReadOnly Property ExposesItsArray As OpcNodeId
```

</div>

**Property value**

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

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

### Mandatory

Gets the identifier of the ModellingRule\_Mandatory object.

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

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

</div>

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

```vbnet
Public ReadOnly Property Mandatory As OpcNodeId
```

</div>

**Property value**

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

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

### MandatoryPlaceholder

Gets the identifier of the ModellingRule\_MandatoryPlaceholder object.

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

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

</div>

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

```vbnet
Public ReadOnly Property MandatoryPlaceholder As OpcNodeId
```

</div>

**Property value**

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

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

### Optional

Gets the identifier of the ModellingRule\_Optional object.

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

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

</div>

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

```vbnet
Public ReadOnly Property [Optional] As OpcNodeId
```

</div>

**Property value**

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

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

### OptionalPlaceholder

Gets the identifier of the ModellingRule\_OptionalPlaceholder object.

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

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

</div>

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

```vbnet
Public ReadOnly Property OptionalPlaceholder As OpcNodeId
```

</div>

**Property value**

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

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