# ImplicitStreamSubscriptionAttribute Constructors

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

## ImplicitStreamSubscriptionAttribute {#constructor-01f2a1e1}

[Dedicated page](/orleans/docs/api/csharp/microsoft.orleans.streaming/orleans.implicitstreamsubscriptionattribute/constructors/constructor-01f2a1e1/)

[Source](https://github.com/dotnet/orleans/blob/e4e752cedecc2976811db49802c7a999b1f1c704/src/Orleans.Streaming/Predicates/StreamSubscriptionAttributes.cs#L34-L37)

```csharp
public ImplicitStreamSubscriptionAttribute()
```

Used to subscribe to all stream namespaces.

## ImplicitStreamSubscriptionAttribute(IStreamNamespacePredicate, string) {#constructor-orleans-streams-istreamnamespacepredicate-string-8343cd54}

[Dedicated page](/orleans/docs/api/csharp/microsoft.orleans.streaming/orleans.implicitstreamsubscriptionattribute/constructors/constructor-orleans-streams-istreamnamespacepredicate-string-8343cd54/)

[Source](https://github.com/dotnet/orleans/blob/e4e752cedecc2976811db49802c7a999b1f1c704/src/Orleans.Streaming/Predicates/StreamSubscriptionAttributes.cs#L68-L72)

```csharp
public ImplicitStreamSubscriptionAttribute(IStreamNamespacePredicate predicate, string streamIdMapper = null)
```

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

### Parameters

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

## ImplicitStreamSubscriptionAttribute(Type, string) {#constructor-system-type-string-1dddc715}

[Dedicated page](/orleans/docs/api/csharp/microsoft.orleans.streaming/orleans.implicitstreamsubscriptionattribute/constructors/constructor-system-type-string-1dddc715/)

[Source](https://github.com/dotnet/orleans/blob/e4e752cedecc2976811db49802c7a999b1f1c704/src/Orleans.Streaming/Predicates/StreamSubscriptionAttributes.cs#L56-L60)

```csharp
public ImplicitStreamSubscriptionAttribute(Type predicateType, string streamIdMapper = null)
```

Allows to pass an arbitrary predicate type to filter stream namespaces to subscribe. The predicate type must have a constructor without parameters.

### Parameters

- `predicateType` (`Type`): The stream namespace predicate type.
- `streamIdMapper` (`string`): The name of the stream identity mapper.

## ImplicitStreamSubscriptionAttribute(string, string) {#constructor-string-string-406fafbc}

[Dedicated page](/orleans/docs/api/csharp/microsoft.orleans.streaming/orleans.implicitstreamsubscriptionattribute/constructors/constructor-string-string-406fafbc/)

[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.