How Can I Efficiently Notify an ObservableCollection of Item Property Changes?

Notify ObservableCollection of Item Changes

Challenge:

ObservableCollection does not automatically detect item changes, even with INotifyPropertyChanged implemented. This can prevent the UI from updating when an item's property changes.

Solution:

To overcome this, consider the following approaches:

TrulyObservableCollection

The TrulyObservableCollection class in the example effectively hooks onto the PropertyChanged events of each item in the collection. However, it raises a Reset CollectionChanged event for every property change, which can be inefficient.

PropertyChanged Event Handling

Alternatively, one can use a regular ObservableCollection and register a PropertyChanged event handler for each item upon CollectionChanged. This helps target specific item changes and avoids unnecessary CollectionChanged events.

Implementation:

In your MyViewModel class, connect the CollectionChanged event of MyItemsSource to the MyItemsSource_CollectionChanged handler. Within this handler:

• Add PropertyChanged event handlers to new items.
• Remove PropertyChanged event handlers from removed items.

When an item's MyProperty changes, the MyType_PropertyChanged handler is invoked. This handler checks if the property name is "MyProperty" and triggers necessary actions if true. This approach is more efficient and provides a clear way to identify item changes.

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