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 # Class ObservableKeyedCollectionBase<TKey, TItem\\>

 Last update: 16.07.2025 

Namespace: [VM.Collections](VM.Collections.md)  
Assembly: VM.dll

```csharp
public abstract class ObservableKeyedCollectionBase<TKey, TItem> : KeyedCollection<TKey, TItem>

```

#### Type Parameters

`TKey`

`TItem`

#### Inheritance

[object](https://learn.microsoft.com/dotnet/api/system.object) ← [Collection&lt;TItem&gt;](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.collection-1) ← [KeyedCollection&lt;TKey, TItem&gt;](https://learn.microsoft.com/dotnet/api/system.collections.objectmodel.keyedcollection-2) ← [ObservableKeyedCollectionBase&lt;TKey, TItem&gt;](VM.Collections.ObservableKeyedCollectionBase-2.md)

## Constructors

### ObservableKeyedCollectionBase()

```csharp
protected ObservableKeyedCollectionBase()

```

## Methods

### &lt;&gt;OnPropertyChanged(PropertyChangedEventArgs)

```csharp
protected void <>OnPropertyChanged(PropertyChangedEventArgs eventArgs)

```

#### Parameters

`eventArgs` [PropertyChangedEventArgs](https://learn.microsoft.com/dotnet/api/system.componentmodel.propertychangedeventargs)

### AddRange(IEnumerable&lt;TItem&gt;)

```csharp
public void AddRange(IEnumerable<TItem> items)

```

#### Parameters

`items` [IEnumerable](https://learn.microsoft.com/dotnet/api/system.collections.generic.ienumerable-1)&lt;TItem&gt;

### ClearItems()

```csharp
protected override void ClearItems()

```

### InsertItem(int, TItem)

```csharp
protected override void InsertItem(int index, TItem item)

```

#### Parameters

`index` [int](https://learn.microsoft.com/dotnet/api/system.int32)

`item` TItem

### OnCollectionChanged(NotifyCollectionChangedEventArgs)

```csharp
protected virtual void OnCollectionChanged(NotifyCollectionChangedEventArgs e)

```

#### Parameters

`e` [NotifyCollectionChangedEventArgs](https://learn.microsoft.com/dotnet/api/system.collections.specialized.notifycollectionchangedeventargs)

### RemoveItem(int)

```csharp
protected override void RemoveItem(int index)

```

#### Parameters

`index` [int](https://learn.microsoft.com/dotnet/api/system.int32)

### SetItem(int, TItem)

```csharp
protected override void SetItem(int index, TItem newitem)

```

#### Parameters

`index` [int](https://learn.microsoft.com/dotnet/api/system.int32)

`newitem` TItem

### TryGetValue(TKey, out TItem)

```csharp
public bool TryGetValue(TKey key, out TItem item)

```

#### Parameters

`key` TKey

`item` TItem

#### Returns

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

### CollectionChanged

```csharp
public event NotifyCollectionChangedEventHandler CollectionChanged

```

#### Event Type

[NotifyCollectionChangedEventHandler](https://learn.microsoft.com/dotnet/api/system.collections.specialized.notifycollectionchangedeventhandler)

### PropertyChanged

```csharp
public event PropertyChangedEventHandler PropertyChanged

```

#### Event Type

[PropertyChangedEventHandler](https://learn.microsoft.com/dotnet/api/system.componentmodel.propertychangedeventhandler)