# OpcFilter Members

> Reference: Provides the entry point to construct filters for monitored items.

<dl class="api-definition">
<dt>Type</dt>
<dd><a href="./">OpcFilter</a></dd>
<dt>Namespace</dt>
<dd><a href="../namespaces/opc.uafx.client">Opc.UaFx.Client</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>

## Methods

### Using

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

Begins the construction of a filter using the `client` specified.

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

```csharp
public static OpcFilterFactory Using(OpcClient client)
```

</div>

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

```vbnet
Public Shared Function [Using](client As OpcClient) As OpcFilterFactory
```

</div>

**Parameters**

| Name | Type | Description |
|---|---|---|
| `client` | [OpcClient](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/) | The [OpcClient](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/) to use to construct the filter. |

**Returns**

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

An [OpcFilterFactory](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcfilterfactory/) which constructs filters using the `client`.

**Exceptions**

| Exception | Condition |
|---|---|
| [ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception) | The `client` is a null reference (Nothing in Visual Basic). |