# OpcQueryEventsCallback Delegate

<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>
</dl>

Represents the method that will refresh / (re)evaluate any node specific conditions to determine pending / occurred events the inquirer should know about.

## Syntax

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

```csharp
public delegate void OpcQueryEventsCallback(
    OpcNodeContext context,
    OpcEventCollection events)
```

</div>

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

```vbnet
Public Delegate Sub OpcQueryEventsCallback(
    context As OpcNodeContext,
    events As OpcEventCollection)
```

</div>

## Parameters

| Name | Type | Description |
|---|---|---|
| `context` | [OpcNodeContext](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodecontext/) | The [OpcNodeContext](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opcnodecontext/) to use to query the node events. |
| `events` | [OpcEventCollection](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opceventcollection/) | The [OpcEventCollection](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.opceventcollection/) to use to store the result of the query. |

## Applies to

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