# ObserverManager<TIdentity, TObserver>

Package: [Microsoft.Orleans.Core](/orleans/docs/api/csharp/microsoft.orleans.core/) 10.0.0

[NuGet package](https://www.nuget.org/packages/Microsoft.Orleans.Core) | [Source](https://github.com/dotnet/orleans/blob/e4e752cedecc2976811db49802c7a999b1f1c704/src/Orleans.Core/Utils/ObserverManager.cs#L40)

```csharp
public class ObserverManager<TIdentity, TObserver> : IEnumerable<TObserver>, IEnumerable
    where TIdentity : notnull
```

Maintains a collection of observers.

## Type parameters

- `TIdentity`: The address type, used to identify observers.
- `TObserver`: The observer type.

## Constructors

- [ObserverManager&lt;TIdentity, TObserver&gt;(TimeSpan, ILogger)](/orleans/docs/api/csharp/microsoft.orleans.core/orleans.utilities.observermanager-2/constructors/constructor-system-timespan-microsoft-extensions-logging-ilogger-7078910e/)

## Properties

- [Count](/orleans/docs/api/csharp/microsoft.orleans.core/orleans.utilities.observermanager-2/properties/count-46fffd77/)
- [ExpirationDuration](/orleans/docs/api/csharp/microsoft.orleans.core/orleans.utilities.observermanager-2/properties/expirationduration-cdff8471/)
- [GetDateTime](/orleans/docs/api/csharp/microsoft.orleans.core/orleans.utilities.observermanager-2/properties/getdatetime-a9e256ab/)
- [Observers](/orleans/docs/api/csharp/microsoft.orleans.core/orleans.utilities.observermanager-2/properties/observers-8b8f3399/)

## Methods

- [Clear](/orleans/docs/api/csharp/microsoft.orleans.core/orleans.utilities.observermanager-2/methods/clear-d74a08f5/)
- [ClearExpired](/orleans/docs/api/csharp/microsoft.orleans.core/orleans.utilities.observermanager-2/methods/clearexpired-ef23d468/)
- [GetEnumerator](/orleans/docs/api/csharp/microsoft.orleans.core/orleans.utilities.observermanager-2/methods/getenumerator-4c25ac37/)
- [Notify(Func&lt;TObserver, Task&gt;, Func&lt;TObserver, bool&gt;)](/orleans/docs/api/csharp/microsoft.orleans.core/orleans.utilities.observermanager-2/methods/notify-system-func-tobserver-system-threading-tasks-task-system-func-tobserver-b-9d109646/)
- [Notify(Action&lt;TObserver&gt;, Func&lt;TObserver, bool&gt;)](/orleans/docs/api/csharp/microsoft.orleans.core/orleans.utilities.observermanager-2/methods/notify-system-action-tobserver-system-func-tobserver-bool-nullable-f2cba9b4/)
- [Subscribe(TIdentity, TObserver)](/orleans/docs/api/csharp/microsoft.orleans.core/orleans.utilities.observermanager-2/methods/subscribe-tidentity-tobserver-aabc0f6d/)
- [Unsubscribe(TIdentity)](/orleans/docs/api/csharp/microsoft.orleans.core/orleans.utilities.observermanager-2/methods/unsubscribe-tidentity-67a346fc/)