# EventingSubscriberServiceCollectionExtensions Methods

- Package: [Aspire.Hosting](/reference/api/csharp/aspire.hosting.md)
- Type: [EventingSubscriberServiceCollectionExtensions](/reference/api/csharp/aspire.hosting/eventingsubscriberservicecollectionextensions.md)
- Kind: `Methods`
- Members: `2`

Provides extension methods for adding event subscribers to the `DependencyInjection.IServiceCollection`.

## AddEventingSubscriber(IServiceCollection)

- Name: `AddEventingSubscriber(IServiceCollection)`
- Modifiers: `extension`
- Source: [GitHub](https://github.com/microsoft/aspire/blob/bd20f904cde09ecb9c9ae5116a6f13614bf2d7c2/src/Aspire.Hosting/Lifecycle/EventingSubscriberServiceCollectionExtensions.cs#L22-L23)

Adds a singleton event subscriber of type `T` to the service collection.

```csharp
public static class EventingSubscriberServiceCollectionExtensions
{
    public static void AddEventingSubscriber<T>(
        this IServiceCollection services)
    {
        // ...
    }
}
```

## Parameters

- `services` (`IServiceCollection`)
  The `DependencyInjection.IServiceCollection` to add the event subscriber to.

## ATS metadata

### Ignored by ATS

- Reason: IServiceCollection is not exported to ATS, and generic service registration is not ATS-compatible. Use IDistributedApplicationBuilder.addEventingSubscriber instead.

## TryAddEventingSubscriber(IServiceCollection)

- Name: `TryAddEventingSubscriber(IServiceCollection)`
- Modifiers: `extension`
- Source: [GitHub](https://github.com/microsoft/aspire/blob/bd20f904cde09ecb9c9ae5116a6f13614bf2d7c2/src/Aspire.Hosting/Lifecycle/EventingSubscriberServiceCollectionExtensions.cs#L33-L34)

Attempts to add a singleton event subscriber of type `T` to the service collection.

```csharp
public static class EventingSubscriberServiceCollectionExtensions
{
    public static void TryAddEventingSubscriber<T>(
        this IServiceCollection services)
    {
        // ...
    }
}
```

## Parameters

- `services` (`IServiceCollection`)
  The `DependencyInjection.IServiceCollection` to add the event subscriber to.

## ATS metadata

### Ignored by ATS

- Reason: IServiceCollection is not exported to ATS, and generic service registration is not ATS-compatible. Use IDistributedApplicationBuilder.tryAddEventingSubscriber instead.