# ImplicitStreamSubscriptionAttribute.ImplicitStreamSubscriptionAttribute(string, string)

[Type overview](/orleans/docs/api/csharp/microsoft.orleans.streaming/orleans.implicitstreamsubscriptionattribute/) | [Constructors](/orleans/docs/api/csharp/microsoft.orleans.streaming/orleans.implicitstreamsubscriptionattribute/constructors/)

[Source](https://github.com/dotnet/orleans/blob/e4e752cedecc2976811db49802c7a999b1f1c704/src/Orleans.Streaming/Predicates/StreamSubscriptionAttributes.cs#L44-L48)

```csharp
public ImplicitStreamSubscriptionAttribute(string streamNamespace, string streamIdMapper = null)
```

Used to subscribe to the specified stream namespace.

### Parameters

- `streamNamespace` (`string`): The stream namespace to subscribe.
- `streamIdMapper` (`string`): The name of the stream identity mapper.