# OpcReferenceTypes Members

> Reference: Provides additional metadata and service routines for the different types of references supported and defined by the OPC UA Foundation Stack.

<dl class="api-definition">
<dt>Type</dt>
<dd><a href="./">OpcReferenceTypes</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>

## Fields

### Aggregates

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [Aggregates](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#aggregates).

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

```csharp
public static readonly OpcNodeId Aggregates
```

</div>

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

```vbnet
Public Shared ReadOnly Aggregates As OpcNodeId
```

</div>

**Field value**

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

### AlwaysGeneratesEvent

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [AlwaysGeneratesEvent](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#alwaysgeneratesevent).

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

```csharp
public static readonly OpcNodeId AlwaysGeneratesEvent
```

</div>

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

```vbnet
Public Shared ReadOnly AlwaysGeneratesEvent As OpcNodeId
```

</div>

**Field value**

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

### FromState

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [FromState](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#fromstate).

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

```csharp
public static readonly OpcNodeId FromState
```

</div>

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

```vbnet
Public Shared ReadOnly FromState As OpcNodeId
```

</div>

**Field value**

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

### GeneratesEvent

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [GeneratesEvent](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#generatesevent).

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

```csharp
public static readonly OpcNodeId GeneratesEvent
```

</div>

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

```vbnet
Public Shared ReadOnly GeneratesEvent As OpcNodeId
```

</div>

**Field value**

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

### HasCause

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [HasCause](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#hascause).

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

```csharp
public static readonly OpcNodeId HasCause
```

</div>

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

```vbnet
Public Shared ReadOnly HasCause As OpcNodeId
```

</div>

**Field value**

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

### HasChild

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [HasChild](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#haschild).

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

```csharp
public static readonly OpcNodeId HasChild
```

</div>

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

```vbnet
Public Shared ReadOnly HasChild As OpcNodeId
```

</div>

**Field value**

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

### HasComponent

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [HasComponent](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#hascomponent).

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

```csharp
public static readonly OpcNodeId HasComponent
```

</div>

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

```vbnet
Public Shared ReadOnly HasComponent As OpcNodeId
```

</div>

**Field value**

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

### HasCondition

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [HasCondition](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#hascondition).

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

```csharp
public static readonly OpcNodeId HasCondition
```

</div>

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

```vbnet
Public Shared ReadOnly HasCondition As OpcNodeId
```

</div>

**Field value**

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

### HasDescription

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [HasDescription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#hasdescription).

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

```csharp
public static readonly OpcNodeId HasDescription
```

</div>

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

```vbnet
Public Shared ReadOnly HasDescription As OpcNodeId
```

</div>

**Field value**

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

### HasEffect

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [HasEffect](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#haseffect).

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

```csharp
public static readonly OpcNodeId HasEffect
```

</div>

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

```vbnet
Public Shared ReadOnly HasEffect As OpcNodeId
```

</div>

**Field value**

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

### HasEncoding

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [HasEncoding](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#hasencoding).

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

```csharp
public static readonly OpcNodeId HasEncoding
```

</div>

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

```vbnet
Public Shared ReadOnly HasEncoding As OpcNodeId
```

</div>

**Field value**

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

### HasEventSource

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [HasEventSource](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#haseventsource).

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

```csharp
public static readonly OpcNodeId HasEventSource
```

</div>

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

```vbnet
Public Shared ReadOnly HasEventSource As OpcNodeId
```

</div>

**Field value**

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

### HasFalseSubState

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [HasFalseSubState](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#hasfalsesubstate).

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

```csharp
public static readonly OpcNodeId HasFalseSubState
```

</div>

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

```vbnet
Public Shared ReadOnly HasFalseSubState As OpcNodeId
```

</div>

**Field value**

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

### HasHistoricalConfiguration

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [HasHistoricalConfiguration](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#hashistoricalconfiguration).

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

```csharp
public static readonly OpcNodeId HasHistoricalConfiguration
```

</div>

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

```vbnet
Public Shared ReadOnly HasHistoricalConfiguration As OpcNodeId
```

</div>

**Field value**

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

### HasModellingRule

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [HasModellingRule](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#hasmodellingrule).

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

```csharp
public static readonly OpcNodeId HasModellingRule
```

</div>

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

```vbnet
Public Shared ReadOnly HasModellingRule As OpcNodeId
```

</div>

**Field value**

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

### HasNotifier

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [HasNotifier](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#hasnotifier).

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

```csharp
public static readonly OpcNodeId HasNotifier
```

</div>

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

```vbnet
Public Shared ReadOnly HasNotifier As OpcNodeId
```

</div>

**Field value**

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

### HasOrderedComponent

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [HasOrderedComponent](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#hasorderedcomponent).

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

```csharp
public static readonly OpcNodeId HasOrderedComponent
```

</div>

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

```vbnet
Public Shared ReadOnly HasOrderedComponent As OpcNodeId
```

</div>

**Field value**

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

### HasProperty

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [HasProperty](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#hasproperty).

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

```csharp
public static readonly OpcNodeId HasProperty
```

</div>

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

```vbnet
Public Shared ReadOnly HasProperty As OpcNodeId
```

</div>

**Field value**

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

### HasSubStateMachine

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [HasSubStateMachine](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#hassubstatemachine).

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

```csharp
public static readonly OpcNodeId HasSubStateMachine
```

</div>

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

```vbnet
Public Shared ReadOnly HasSubStateMachine As OpcNodeId
```

</div>

**Field value**

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

### HasSubtype

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [HasSubtype](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#hassubtype).

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

```csharp
public static readonly OpcNodeId HasSubtype
```

</div>

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

```vbnet
Public Shared ReadOnly HasSubtype As OpcNodeId
```

</div>

**Field value**

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

### HasTrueSubState

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [HasTrueSubState](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#hastruesubstate).

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

```csharp
public static readonly OpcNodeId HasTrueSubState
```

</div>

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

```vbnet
Public Shared ReadOnly HasTrueSubState As OpcNodeId
```

</div>

**Field value**

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

### HasTypeDefinition

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [HasTypeDefinition](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#hastypedefinition).

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

```csharp
public static readonly OpcNodeId HasTypeDefinition
```

</div>

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

```vbnet
Public Shared ReadOnly HasTypeDefinition As OpcNodeId
```

</div>

**Field value**

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

### HierarchicalReferences

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [HierarchicalReferences](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#hierarchicalreferences).

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

```csharp
public static readonly OpcNodeId HierarchicalReferences
```

</div>

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

```vbnet
Public Shared ReadOnly HierarchicalReferences As OpcNodeId
```

</div>

**Field value**

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

### NonHierarchicalReferences

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [NonHierarchicalReferences](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#nonhierarchicalreferences).

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

```csharp
public static readonly OpcNodeId NonHierarchicalReferences
```

</div>

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

```vbnet
Public Shared ReadOnly NonHierarchicalReferences As OpcNodeId
```

</div>

**Field value**

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

### Organizes

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [Organizes](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#organizes).

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

```csharp
public static readonly OpcNodeId Organizes
```

</div>

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

```vbnet
Public Shared ReadOnly Organizes As OpcNodeId
```

</div>

**Field value**

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

### References

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [References](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#references).

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

```csharp
public static readonly OpcNodeId References
```

</div>

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

```vbnet
Public Shared ReadOnly References As OpcNodeId
```

</div>

**Field value**

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

### ToState

<span class="api-meta">static</span>

Provides the identifier used by references representing the reference type [ToState](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/#tostate).

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

```csharp
public static readonly OpcNodeId ToState
```

</div>

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

```vbnet
Public Shared ReadOnly ToState As OpcNodeId
```

</div>

**Field value**

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

## Methods

### GetNodeId

<span class="api-meta">static</span>

Retrieves the according [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) for the type of reference defined by the [OpcReferenceType](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/) specified by `type`.

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

```csharp
public static OpcNodeId GetNodeId(OpcReferenceType type)
```

</div>

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

```vbnet
Public Shared Function GetNodeId(type As OpcReferenceType) As OpcNodeId
```

</div>

**Parameters**

| Name | Type | Description |
|---|---|---|
| `type` | [OpcReferenceType](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/) | The [OpcReferenceType](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/) value from which the according [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) of the reference type is to be determined. |

**Returns**

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

The [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) of the reference type the `type` refer to or a null reference (Nothing in Visual Basic) if the `type` is not a foundation defined reference type.

### GetReferenceType

<span class="api-meta">static · 2 overloads</span>

| Overload | Description |
|---|---|
| [GetReferenceType(OpcNodeId)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetypes/members#getreferencetype-opc-uafx-opcnodeid)<span class="api-meta">static</span> | Retrieves the according [OpcReferenceType](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/) enumeration member for the `nodeId` used by a specified type of reference. |
| [GetReferenceType(OpcName)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetypes/members#getreferencetype-opc-uafx-opcname)<span class="api-meta">static · since v2.18</span> | Retrieves the according [OpcReferenceType](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/) enumeration member for the `name` used by a specified type of reference. |

#### GetReferenceType(OpcNodeId)

<span class="api-meta">static</span>

Retrieves the according [OpcReferenceType](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/) enumeration member for the `nodeId` used by a specified type of reference.

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

```csharp
public static OpcReferenceType? GetReferenceType(OpcNodeId nodeId)
```

</div>

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

```vbnet
Public Shared Function GetReferenceType(
    nodeId As OpcNodeId) As OpcReferenceType?
```

</div>

**Parameters**

| Name | Type | Description |
|---|---|---|
| `nodeId` | [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) | The identifier of the type of reference used by an instance node (see 'Opc.UaFx.OpcInstanceNode.ReferenceType'). |

**Returns**

[Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)&lt;[OpcReferenceType](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/)&gt;

One of the members defined by the [OpcReferenceType](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/) enumeration which represents the type identifier specified or a null reference (Nothing in Visual Basic) if the specific type of reference can't be determined.

#### GetReferenceType(OpcName)

<span class="api-meta">static · since v2.18</span>

Retrieves the according [OpcReferenceType](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/) enumeration member for the `name` used by a specified type of reference.

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

```csharp
public static OpcReferenceType? GetReferenceType(OpcName name)
```

</div>

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

```vbnet
Public Shared Function GetReferenceType(name As OpcName) As OpcReferenceType?
```

</div>

**Parameters**

| Name | Type | Description |
|---|---|---|
| `name` | [OpcName](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcname/) | The [OpcName](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcname/) indicating the [BrowseName](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#browsename) of the type of reference to resolve. |

**Returns**

[Nullable](https://learn.microsoft.com/dotnet/api/system.nullable-1)&lt;[OpcReferenceType](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/)&gt;

One of the members defined by the [OpcReferenceType](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreferencetype/) enumeration which represents the type name specified or a null reference (Nothing in Visual basic) if the specified type of reference can't be determined.

### GetReferenceTypeName

<span class="api-meta">static · since v2.18</span>

Retrieves the according [OpcName](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcname/) indicating the [BrowseName](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcattribute/#browsename) of the type of reference identified by `nodeId`.

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

```csharp
public static OpcName GetReferenceTypeName(OpcNodeId nodeId)
```

</div>

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

```vbnet
Public Shared Function GetReferenceTypeName(nodeId As OpcNodeId) As OpcName
```

</div>

**Parameters**

| Name | Type | Description |
|---|---|---|
| `nodeId` | [OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/) | The identifier of the type of reference. |

**Returns**

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

The [OpcName](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcname/) of the type of reference identified by `nodeId` or a null reference (Nothing in Visual Basic) if the specific type of reference can't be determined.