# <a id="Aeon_Environment_ActiveSubjectCollection"></a> Class ActiveSubjectCollection

Namespace: [Aeon.Environment](Aeon.Environment.md)  
Assembly: Aeon.Environment.dll  

```csharp
public class ActiveSubjectCollection : KeyedCollection<string, EnvironmentSubjectStateEntry>, IList<EnvironmentSubjectStateEntry>, ICollection<EnvironmentSubjectStateEntry>, IList, ICollection, IReadOnlyList<EnvironmentSubjectStateEntry>, IReadOnlyCollection<EnvironmentSubjectStateEntry>, IEnumerable<EnvironmentSubjectStateEntry>, IEnumerable
```

#### Inheritance

[object](https://learn.microsoft.com/dotnet/api/system.object) ← 
[Collection<EnvironmentSubjectStateEntry\>](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.collection\-1) ← 
[KeyedCollection<string, EnvironmentSubjectStateEntry\>](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.keyedcollection\-2) ← 
[ActiveSubjectCollection](Aeon.Environment.ActiveSubjectCollection.md)

#### Implements

[IList<EnvironmentSubjectStateEntry\>](https://learn.microsoft.com/dotnet/api/system.collections.generic.ilist\-1), 
[ICollection<EnvironmentSubjectStateEntry\>](https://learn.microsoft.com/dotnet/api/system.collections.generic.icollection\-1), 
[IList](https://learn.microsoft.com/dotnet/api/system.collections.ilist), 
[ICollection](https://learn.microsoft.com/dotnet/api/system.collections.icollection), 
[IReadOnlyList<EnvironmentSubjectStateEntry\>](https://learn.microsoft.com/dotnet/api/system.collections.generic.ireadonlylist\-1), 
[IReadOnlyCollection<EnvironmentSubjectStateEntry\>](https://learn.microsoft.com/dotnet/api/system.collections.generic.ireadonlycollection\-1), 
[IEnumerable<EnvironmentSubjectStateEntry\>](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable\-1), 
[IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.ienumerable)

#### Inherited Members

[KeyedCollection<string, EnvironmentSubjectStateEntry\>.Contains\(string\)](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.keyedcollection\-2.contains), 
[KeyedCollection<string, EnvironmentSubjectStateEntry\>.Remove\(string\)](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.keyedcollection\-2.remove), 
[KeyedCollection<string, EnvironmentSubjectStateEntry\>.ChangeItemKey\(EnvironmentSubjectStateEntry, string\)](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.keyedcollection\-2.changeitemkey), 
[KeyedCollection<string, EnvironmentSubjectStateEntry\>.ClearItems\(\)](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.keyedcollection\-2.clearitems), 
[KeyedCollection<string, EnvironmentSubjectStateEntry\>.GetKeyForItem\(EnvironmentSubjectStateEntry\)](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.keyedcollection\-2.getkeyforitem), 
[KeyedCollection<string, EnvironmentSubjectStateEntry\>.InsertItem\(int, EnvironmentSubjectStateEntry\)](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.keyedcollection\-2.insertitem), 
[KeyedCollection<string, EnvironmentSubjectStateEntry\>.RemoveItem\(int\)](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.keyedcollection\-2.removeitem), 
[KeyedCollection<string, EnvironmentSubjectStateEntry\>.SetItem\(int, EnvironmentSubjectStateEntry\)](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.keyedcollection\-2.setitem), 
[KeyedCollection<string, EnvironmentSubjectStateEntry\>.Comparer](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.keyedcollection\-2.comparer), 
[KeyedCollection<string, EnvironmentSubjectStateEntry\>.this\[string\]](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.keyedcollection\-2.item), 
[KeyedCollection<string, EnvironmentSubjectStateEntry\>.Dictionary](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.keyedcollection\-2.dictionary), 
[Collection<EnvironmentSubjectStateEntry\>.Add\(EnvironmentSubjectStateEntry\)](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.collection\-1.add), 
[Collection<EnvironmentSubjectStateEntry\>.Clear\(\)](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.collection\-1.clear), 
[Collection<EnvironmentSubjectStateEntry\>.CopyTo\(EnvironmentSubjectStateEntry\[\], int\)](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.collection\-1.copyto), 
[Collection<EnvironmentSubjectStateEntry\>.Contains\(EnvironmentSubjectStateEntry\)](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.collection\-1.contains), 
[Collection<EnvironmentSubjectStateEntry\>.GetEnumerator\(\)](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.collection\-1.getenumerator), 
[Collection<EnvironmentSubjectStateEntry\>.IndexOf\(EnvironmentSubjectStateEntry\)](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.collection\-1.indexof), 
[Collection<EnvironmentSubjectStateEntry\>.Insert\(int, EnvironmentSubjectStateEntry\)](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.collection\-1.insert), 
[Collection<EnvironmentSubjectStateEntry\>.Remove\(EnvironmentSubjectStateEntry\)](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.collection\-1.remove), 
[Collection<EnvironmentSubjectStateEntry\>.RemoveAt\(int\)](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.collection\-1.removeat), 
[Collection<EnvironmentSubjectStateEntry\>.ClearItems\(\)](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.collection\-1.clearitems), 
[Collection<EnvironmentSubjectStateEntry\>.InsertItem\(int, EnvironmentSubjectStateEntry\)](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.collection\-1.insertitem), 
[Collection<EnvironmentSubjectStateEntry\>.RemoveItem\(int\)](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.collection\-1.removeitem), 
[Collection<EnvironmentSubjectStateEntry\>.SetItem\(int, EnvironmentSubjectStateEntry\)](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.collection\-1.setitem), 
[Collection<EnvironmentSubjectStateEntry\>.Count](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.collection\-1.count), 
[Collection<EnvironmentSubjectStateEntry\>.Items](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.collection\-1.items), 
[Collection<EnvironmentSubjectStateEntry\>.this\[int\]](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.collection\-1.item), 
[object.ToString\(\)](https://learn.microsoft.com/dotnet/api/system.object.tostring), 
[object.Equals\(object\)](https://learn.microsoft.com/dotnet/api/system.object.equals\#system\-object\-equals\(system\-object\)), 
[object.Equals\(object, object\)](https://learn.microsoft.com/dotnet/api/system.object.equals\#system\-object\-equals\(system\-object\-system\-object\)), 
[object.ReferenceEquals\(object, object\)](https://learn.microsoft.com/dotnet/api/system.object.referenceequals), 
[object.GetHashCode\(\)](https://learn.microsoft.com/dotnet/api/system.object.gethashcode), 
[object.GetType\(\)](https://learn.microsoft.com/dotnet/api/system.object.gettype), 
[object.MemberwiseClone\(\)](https://learn.microsoft.com/dotnet/api/system.object.memberwiseclone)

## Methods

### <a id="Aeon_Environment_ActiveSubjectCollection_GetKeyForItem_Aeon_Environment_EnvironmentSubjectStateEntry_"></a> GetKeyForItem\(EnvironmentSubjectStateEntry\)

When implemented in a derived class, extracts the key from the specified element.

```csharp
protected override string GetKeyForItem(EnvironmentSubjectStateEntry item)
```

#### Parameters

`item` [EnvironmentSubjectStateEntry](Aeon.Environment.EnvironmentSubjectStateEntry.md)

The element from which to extract the key.

#### Returns

 [string](https://learn.microsoft.com/dotnet/api/system.string)

The key for the specified element.