# OpcSubscriptionChangedEventHandler Delegate

> Reference: Represents the method that will handle the Changed event.

<dl class="api-definition">
<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>

Represents the method that will handle the [Changed](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/members#changed) event.

## Syntax

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

```csharp
public delegate void OpcSubscriptionChangedEventHandler(
    object sender,
    OpcSubscriptionChangedEventArgs e)
```

</div>

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

```vbnet
Public Delegate Sub OpcSubscriptionChangedEventHandler(
    sender As Object,
    e As OpcSubscriptionChangedEventArgs)
```

</div>

## Parameters

| Name | Type | Description |
|---|---|---|
| `sender` | [Object](https://learn.microsoft.com/dotnet/api/system.object) | The source of the event (an instance of the [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/) class). |
| `e` | [OpcSubscriptionChangedEventArgs](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionchangedeventargs/) | An instance of the [OpcSubscriptionChangedEventArgs](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscriptionchangedeventargs/) class containing the event data. |

## Applies to

| Package | Versions |
|---|---|
| Opc.UaFx.Advanced | v2.5–v2.59 |