# OpcNodeTypeSystem Members

> Reference: Represents a system which defines type information used as templates to initialize different types of nodes.

<dl class="api-definition">
<dt>Type</dt>
<dd><a href="./">OpcNodeTypeSystem</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 [OpcTypeSystem&lt;OpcNodeTypeInfo&gt;](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opctypesystem-1/members).

## Properties

### Context

<span class="api-meta">abstract · since v2.50</span>

Gets the [OpcContext](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opccontext/) used by this [OpcNodeTypeSystem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/).

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

```csharp
public abstract OpcContext Context { get; }
```

</div>

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

```vbnet
Public MustOverride ReadOnly Property Context As OpcContext
```

</div>

**Property value**

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

A [OpcContext](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opccontext/) used by this this [OpcNodeTypeSystem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/).

### Current

<span class="api-meta">static · since v2.20</span>

Gets the type system used by the Client or Server application.

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

```csharp
public static OpcNodeTypeSystem Current { get; }
```

</div>

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

```vbnet
Public Shared ReadOnly Property Current As OpcNodeTypeSystem
```

</div>

**Property value**

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

An instance of the [OpcNodeTypeSystem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/) class which contains the types described by the [Type](https://learn.microsoft.com/dotnet/api/system.type)s using the [OpcDataTypeAttribute](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcdatatypeattribute/) implemented in the application which uses the OPC UA SDK.

### Default

<span class="api-meta">static · since v2.20</span>

Gets the default type system used by the OPC UA stack.

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

```csharp
public static OpcNodeTypeSystem Default { get; }
```

</div>

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

```vbnet
Public Shared ReadOnly Property [Default] As OpcNodeTypeSystem
```

</div>

**Property value**

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

An instance of the [OpcNodeTypeSystem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/) class which contains the types used by default in Client and Server applications.

**Remarks**

The information offered by the default [OpcNodeTypeSystem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/) is embedded in the OPC UA SDK and is therefore determined from the resources of the assembly whenever required.

### Empty

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

Gets the type system to use if their is no specific type system data available.

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

```csharp
public static OpcNodeTypeSystem Empty { get; }
```

</div>

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

```vbnet
Public Shared ReadOnly Property Empty As OpcNodeTypeSystem
```

</div>

**Property value**

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

An instance of the [OpcNodeTypeSystem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/) class which contains no type information.

### HasCachedTypes

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

Gets a value indicating whether the type system already has determined at least some type information offered as [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) objects.

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

```csharp
protected bool HasCachedTypes { get; }
```

</div>

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

```vbnet
Protected ReadOnly Property HasCachedTypes As Boolean
```

</div>

**Property value**

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

The value true if the system offers already prepared [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) objects; otherwise the value false.

### HasCachingCompleted

<span class="api-meta">protected · virtual</span>

Gets a value indicating whether the type system has determined the whole type information offered as [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) objects.

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

```csharp
protected virtual bool HasCachingCompleted { get; }
```

</div>

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

```vbnet
Protected Overridable Property HasCachingCompleted As Boolean
```

</div>

**Property value**

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

The value true if the system has completed its type information retrieval and will use its internal cache to determine [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) objects; otherwise the value false.

## Methods

### GetTypeCore

<span class="api-meta">protected · override · 4 overloads</span>

| Overload | Description |
|---|---|
| [GetTypeCore(string)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/members#gettypecore-system-string)<span class="api-meta">protected · override</span> | Retrieves the [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) object which is known under the `name` specified. |
| [GetTypeCore(OpcName)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/members#gettypecore-opc-uafx-opcname)<span class="api-meta">protected · override</span> | Retrieves the [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) object which is known under the `name` specified. |
| [GetTypeCore(OpcNodeId)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/members#gettypecore-opc-uafx-opcnodeid)<span class="api-meta">protected · override</span> | Retrieves the [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) object which declares the type which is identified by the `typeId` specified. |
| [GetTypeCore(Type)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/members#gettypecore-system-type)<span class="api-meta">protected · override</span> | Retrieves the [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) object which declares the type implemented by the `underlyingType` specified. |

#### GetTypeCore(string)

<span class="api-meta">protected · override</span>

Retrieves the [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) object which is known under the `name` specified.

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

```csharp
protected override OpcNodeTypeInfo GetTypeCore(string name)
```

</div>

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

```vbnet
Protected Overrides Function GetTypeCore(name As String) As OpcNodeTypeInfo
```

</div>

**Parameters**

| Name | Type | Description |
|---|---|---|
| `name` | [String](https://learn.microsoft.com/dotnet/api/system.string) | The [string](https://learn.microsoft.com/dotnet/api/system.string) to use to identify the [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) object to retrieve. |

**Returns**

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

The [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) object its [Name](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/members#name) is equals (regarding its [Value](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcname/members#value)) to the `name` specified; otherwise a null reference (Nothing in Visual Basic).

**Overrides**

[GetTypeCore(string)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opctypesystem-1/members#gettypecore-system-string)

**Remarks**

It is already assured that the passed `name` is not a null reference (Nothing in Visual Basic) nor equals [Empty](https://learn.microsoft.com/dotnet/api/system.string.empty). In case there this method is not implemented in a derived class this method determines the type from a distinct and on-demand determined sequence which combines the [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) objects offered by [RetrieveTypesCore](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/members#retrievetypescore-noparams) and [RetrieveTypesCore](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/members#retrievetypescore-system-collections-generic-idictionary-of-opc-uafx-opcnodeid-opc-uafx-opcnodetypeinfo). Both methods are called only once and their output is cached for subsequent type information retrieval.

#### GetTypeCore(OpcName)

<span class="api-meta">protected · override</span>

Retrieves the [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) object which is known under the `name` specified.

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

```csharp
protected override OpcNodeTypeInfo GetTypeCore(OpcName name)
```

</div>

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

```vbnet
Protected Overrides Function GetTypeCore(name As OpcName) As OpcNodeTypeInfo
```

</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/) of the [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) object to retrieve. |

**Returns**

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

The [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) object its [Name](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/members#name) is equals to the `name` specified; otherwise a null reference (Nothing in Visual Basic).

**Overrides**

[GetTypeCore(OpcName)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opctypesystem-1/members#gettypecore-opc-uafx-opcname)

**Remarks**

It is already assured that the passed `name` is not a null reference (Nothing in Visual Basic). In case there this method is not implemented in a derived class this method determines the type from a distinct and on-demand determined sequence which combines the [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) objects offered by [RetrieveTypesCore](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/members#retrievetypescore-noparams) and [RetrieveTypesCore](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/members#retrievetypescore-system-collections-generic-idictionary-of-opc-uafx-opcnodeid-opc-uafx-opcnodetypeinfo). Both methods are called only once and their output is cached for subsequent type information retrieval.

#### GetTypeCore(OpcNodeId)

<span class="api-meta">protected · override</span>

Retrieves the [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) object which declares the type which is identified by the `typeId` specified.

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

```csharp
protected override OpcNodeTypeInfo GetTypeCore(OpcNodeId typeId)
```

</div>

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

```vbnet
Protected Overrides Function GetTypeCore(typeId As OpcNodeId) As OpcNodeTypeInfo
```

</div>

**Parameters**

| Name | Type | Description |
|---|---|---|
| `typeId` | [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/) which identifies the [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) to retrieve. |

**Returns**

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

The [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) object which is known under the `typeId` specified or a null reference (Nothing in Visual Basic) if there doesn't exist a known [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) object which is associated with the `typeId` specified.

**Overrides**

[GetTypeCore(OpcNodeId)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opctypesystem-1/members#gettypecore-opc-uafx-opcnodeid)

**Remarks**

It is already assured that the passed `typeId` is not a null reference (Nothing in Visual Basic). In case there this method is not implemented in a derived class this method determines the type from a distinct and on-demand determined sequence which combines the [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) objects offered by [RetrieveTypesCore](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/members#retrievetypescore-noparams) and [RetrieveTypesCore](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/members#retrievetypescore-system-collections-generic-idictionary-of-opc-uafx-opcnodeid-opc-uafx-opcnodetypeinfo). Both methods are called only once and their output is cached for subsequent type information retrieval.

#### GetTypeCore(Type)

<span class="api-meta">protected · override</span>

Retrieves the [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) object which declares the type implemented by the `underlyingType` specified.

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

```csharp
protected override OpcNodeTypeInfo GetTypeCore(Type underlyingType)
```

</div>

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

```vbnet
Protected Overrides Function GetTypeCore(
    underlyingType As Type) As OpcNodeTypeInfo
```

</div>

**Parameters**

| Name | Type | Description |
|---|---|---|
| `underlyingType` | [Type](https://learn.microsoft.com/dotnet/api/system.type) | The [Type](https://learn.microsoft.com/dotnet/api/system.type) which implements the [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) to retrieve. |

**Returns**

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

The [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) object which declares the `underlyingType` specified or a null reference (Nothing in Visual Basic) if there isn't a [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) object associated with the `underlyingType` specified.

**Overrides**

[GetTypeCore(Type)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opctypesystem-1/members#gettypecore-system-type)

**Remarks**

It is already assured that the passed `underlyingType` is not a null reference (Nothing in Visual Basic). In case there this method is not implemented in a derived class this method determines the type from a distinct and on-demand determined sequence which combines the [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) objects offered by [RetrieveTypesCore](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/members#retrievetypescore-noparams) and [RetrieveTypesCore](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/members#retrievetypescore-system-collections-generic-idictionary-of-opc-uafx-opcnodeid-opc-uafx-opcnodetypeinfo). Both methods are called only once and their output is cached for subsequent type information retrieval.

### GetTypesCore

<span class="api-meta">protected · override</span>

Retrieves all [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) objects offered by the current [OpcNodeTypeSystem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/) .

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

```csharp
protected override OpcNodeTypeInfo[] GetTypesCore()
```

</div>

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

```vbnet
Protected Overrides Function GetTypesCore() As OpcNodeTypeInfo()
```

</div>

**Returns**

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

An array that contains all [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) objects that are offered by the [OpcNodeTypeSystem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/).

**Overrides**

[GetTypesCore()](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opctypesystem-1/members#gettypescore)

### RetrieveTypesCore

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

| Overload | Description |
|---|---|
| [RetrieveTypesCore()](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/members#retrievetypescore-noparams)<span class="api-meta">protected</span> | Retrieves all [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) objects explictly offered by the [OpcNodeTypeSystem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/). |
| [RetrieveTypesCore(IDictionary&lt;OpcNodeId, OpcNodeTypeInfo&gt;)](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/members#retrievetypescore-system-collections-generic-idictionary-of-opc-uafx-opcnodeid-opc-uafx-opcnodetypeinfo)<span class="api-meta">protected · virtual</span> | When implemented in a derived class, retrieves all [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) objects on-demand offered by the [OpcNodeTypeSystem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/) except the already `knownTypes` specified. |

#### RetrieveTypesCore()

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

Retrieves all [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) objects explictly offered by the [OpcNodeTypeSystem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/).

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

```csharp
protected IDictionary<OpcNodeId, OpcNodeTypeInfo> RetrieveTypesCore()
```

</div>

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

```vbnet
Protected Function RetrieveTypesCore() As IDictionary(Of OpcNodeId, OpcNodeTypeInfo)
```

</div>

**Returns**

[IDictionary](https://learn.microsoft.com/dotnet/api/system.collections.generic.idictionary-2)&lt;[OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/), [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/)&gt;

A dictionary of explictly offered [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) objects.

#### RetrieveTypesCore(IDictionary&lt;OpcNodeId, OpcNodeTypeInfo&gt;)

<span class="api-meta">protected · virtual</span>

When implemented in a derived class, retrieves all [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) objects on-demand offered by the [OpcNodeTypeSystem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/) except the already `knownTypes` specified.

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

```csharp
protected virtual IEnumerable<OpcNodeTypeInfo> RetrieveTypesCore(
    IDictionary<OpcNodeId, OpcNodeTypeInfo> knownTypes)
```

</div>

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

```vbnet
Protected Overridable Function RetrieveTypesCore(
    knownTypes As IDictionary(Of OpcNodeId, OpcNodeTypeInfo)) As IEnumerable(Of OpcNodeTypeInfo)
```

</div>

**Parameters**

| Name | Type | Description |
|---|---|---|
| `knownTypes` | [IDictionary](https://learn.microsoft.com/dotnet/api/system.collections.generic.idictionary-2)&lt;[OpcNodeId](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodeid/), [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/)&gt; | The dictionary of already known [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) objects which shall not be offered. |

**Returns**

[IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)&lt;[OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/)&gt;

A sequence of [OpcNodeTypeInfo](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypeinfo/) objects offered by the [OpcNodeTypeSystem](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodetypesystem/) except the types in `knownTypes`.