# OpcDataChangeReceivedEventHandler Delegate

> Reference: Represents the method that will handle DataChangeReceived, DataChangeReceived and DataChangeReceived events.

<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 [DataChangeReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcclient/datachangereceived), [DataChangeReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcsubscription/members#datachangereceived) and [DataChangeReceived](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.client.opcmonitoreditem/members#datachangereceived) events.

## Syntax

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

```csharp
public delegate void OpcDataChangeReceivedEventHandler(
    object sender,
    OpcDataChangeReceivedEventArgs e)
```

</div>

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

```vbnet
Public Delegate Sub OpcDataChangeReceivedEventHandler(
    sender As Object,
    e As OpcDataChangeReceivedEventArgs)
```

</div>

## Parameters

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

## Applies to

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