# DistributedApplicationEventSubscription Properties

- Package: [Aspire.Hosting](/reference/api/csharp/aspire.hosting.md)
- Type: [DistributedApplicationEventSubscription](/reference/api/csharp/aspire.hosting/distributedapplicationeventsubscription.md)
- Kind: `Properties`
- Members: `1`

Represents a subscription to an event that is published during the lifecycle of the AppHost.

## Callback

- Name: `Callback`
- Modifiers: `get`
- Returns: `Func<IDistributedApplicationEvent, CancellationToken, Task>`
- Source: [GitHub](https://github.com/microsoft/aspire/blob/bd20f904cde09ecb9c9ae5116a6f13614bf2d7c2/src/Aspire.Hosting/Eventing/DistributedApplicationEventSubscription.cs#L18)

The callback to be executed when the event is published.

```csharp
public Func<IDistributedApplicationEvent, CancellationToken, Task> Callback { get; }
```