# ChronologicalEvictionStrategy Properties

[Type overview](/orleans/docs/api/csharp/microsoft.orleans.streaming/orleans.providers.streams.common.chronologicalevictionstrategy/)

## OnPurged {#onpurged-e949c930}

[Dedicated page](/orleans/docs/api/csharp/microsoft.orleans.streaming/orleans.providers.streams.common.chronologicalevictionstrategy/properties/onpurged-e949c930/)

[Source](https://github.com/dotnet/orleans/blob/e4e752cedecc2976811db49802c7a999b1f1c704/src/Orleans.Streaming/Common/PooledCache/ChronologicalEvictionStrategy.cs)

```csharp
public Action<CachedMessage?, CachedMessage?> OnPurged
```

Gets or sets the method which will be called when purge is finished.

## PurgeObservable {#purgeobservable-a49cca1d}

[Dedicated page](/orleans/docs/api/csharp/microsoft.orleans.streaming/orleans.providers.streams.common.chronologicalevictionstrategy/properties/purgeobservable-a49cca1d/)

[Source](https://github.com/dotnet/orleans/blob/e4e752cedecc2976811db49802c7a999b1f1c704/src/Orleans.Streaming/Common/PooledCache/ChronologicalEvictionStrategy.cs)

```csharp
public IPurgeObservable PurgeObservable
```

Gets the [IPurgeObservable](/orleans/docs/api/csharp/microsoft.orleans.streaming/orleans.providers.streams.common.ipurgeobservable/), which is implemented by the cache to do purge related actions and invoked by the eviction strategy.