# OpcReadOnlyNamespaceCollection Class

> Reference: Provides a read-only collection of OpcNamespace instances.

<span class="api-meta">since v2.9</span>

<dl class="api-definition">
<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>Members</dt>
<dd><a href="./members">OpcReadOnlyNamespaceCollection Members</a></dd>
<dt>Also in</dt>
<dd>Opc.UaFx.Client</dd>
</dl>

Provides a read-only collection of [OpcNamespace](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnamespace/) instances.

## Syntax

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

```csharp
public class OpcReadOnlyNamespaceCollection : ReadOnlyCollection<OpcNamespace>
```

</div>

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

```vbnet
Public Class OpcReadOnlyNamespaceCollection
    Inherits ReadOnlyCollection(Of OpcNamespace)
```

</div>

## Inheritance

[Object](https://learn.microsoft.com/dotnet/api/system.object) → [ReadOnlyCollection](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.readonlycollection-1)&lt;[OpcNamespace](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnamespace/)&gt; → **OpcReadOnlyNamespaceCollection**

## Implements

<ul class="api-implements">
<li><a href="https://learn.microsoft.com/dotnet/api/system.collections.icollection">ICollection</a></li>
<li><a href="https://learn.microsoft.com/dotnet/api/system.collections.generic.icollection-1">ICollection</a>&lt;<a href="../opc.uafx.opcnamespace/">OpcNamespace</a>&gt;</li>
<li><a href="https://learn.microsoft.com/dotnet/api/system.collections.ienumerable">IEnumerable</a></li>
<li><a href="https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1">IEnumerable</a>&lt;<a href="../opc.uafx.opcnamespace/">OpcNamespace</a>&gt;</li>
<li><a href="https://learn.microsoft.com/dotnet/api/system.collections.ilist">IList</a></li>
<li><a href="https://learn.microsoft.com/dotnet/api/system.collections.generic.ilist-1">IList</a>&lt;<a href="../opc.uafx.opcnamespace/">OpcNamespace</a>&gt;</li>
<li><a href="../opc.uafx.iopcnamespaceresolver/">IOpcNamespaceResolver</a></li>
<li><a href="https://learn.microsoft.com/dotnet/api/system.collections.generic.ireadonlycollection-1">IReadOnlyCollection</a>&lt;<a href="../opc.uafx.opcnamespace/">OpcNamespace</a>&gt;</li>
<li><a href="https://learn.microsoft.com/dotnet/api/system.collections.generic.ireadonlylist-1">IReadOnlyList</a>&lt;<a href="../opc.uafx.opcnamespace/">OpcNamespace</a>&gt;</li>
</ul>

## Constructors

| Name | Description |
|---|---|
| [OpcReadOnlyNamespaceCollection](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreadonlynamespacecollection/members#opcreadonlynamespacecollection) | Initializes a new instance of the OpcReadOnlyNamespaceCollection class that is a read-only wrapper around the specified `list`. |

## Methods

| Name | Description |
|---|---|
| [Resolve](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreadonlynamespacecollection/members#resolve)<span class="api-meta">since v2.12</span> | Resolves another namespace using the information in the `source` specified. |
| [ResolveIndex](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreadonlynamespacecollection/members#resolveindex)<span class="api-meta">since v2.12</span> | Resolves the unique identifier of the namespace specified by the `namespaceValue`. |
| [ResolveValue](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcreadonlynamespacecollection/members#resolvevalue)<span class="api-meta">since v2.12</span> | Resolves the [string](https://learn.microsoft.com/dotnet/api/system.string)-based representation of the namespace which can be identified using the `namespaceIndex` specified. |

Inherits members from [ReadOnlyCollection&lt;OpcNamespace&gt;](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.readonlycollection-1).

## Applies to

| Package | Versions |
|---|---|
| Opc.UaFx.Advanced | v2.9–v2.59 |