# ImplicitChannelSubscriptionAttribute.ImplicitChannelSubscriptionAttribute(IChannelNamespacePredicate, string)

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

[Source](https://github.com/dotnet/orleans/blob/e4e752cedecc2976811db49802c7a999b1f1c704/src/Orleans.BroadcastChannel/SubscriberTable/Predicates/ImplicitChannelSubscriptionAttribute.cs#L65-L69)

```csharp
public ImplicitChannelSubscriptionAttribute(IChannelNamespacePredicate predicate, string channelIdMapper = null)
```

Allows to pass an instance of the stream namespace predicate. To be used mainly as an extensibility point via inheriting attributes.

### Parameters

- `predicate` (`IChannelNamespacePredicate`): The stream namespace predicate.
- `channelIdMapper` (`string`): The name of the stream identity mapper.