# DistributedApplicationEventSubscription Constructors

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

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

## DistributedApplicationEventSubscription(Func<IDistributedApplicationEvent, CancellationToken, Task>)

- Name: `Constructor(Func<IDistributedApplicationEvent, CancellationToken, Task>)`
- Source: [GitHub](https://github.com/microsoft/aspire/blob/bd20f904cde09ecb9c9ae5116a6f13614bf2d7c2/src/Aspire.Hosting/Eventing/DistributedApplicationEventSubscription.cs#L13-L18)

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

```csharp
public class DistributedApplicationEventSubscription
{
    public DistributedApplicationEventSubscription(
        Func<IDistributedApplicationEvent, CancellationToken, Task> callback)
    {
        // ...
    }
}
```

## Parameters

- `callback` (`Func<IDistributedApplicationEvent, CancellationToken, Task>`)
  Callback to invoke when the event is published.