All 6 Advanced Data Binding & Collections questions
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How do you bind to nested properties and handle null paths safely? What is RelativeSource binding and when do you need it? How do you implement input validation with data binding? How do you efficiently update large observable collections? How do you implement grouping in a CollectionView?
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.NET MAUI › Advanced Data Binding & Collections

What is ObservableCollection and why use it for lists?

Beginner

Answer

ObservableCollection<T> implements INotifyCollectionChanged, so adding/removing items automatically updates a bound CollectionView without rebinding. Use it for dynamic lists. Note that replacing the whole collection still requires a property change notification on the property holding it.
public ObservableCollection<Item> Items { get; } = new();
Items.Add(newItem);   // UI updates automatically
Real-world example A chat list appends incoming messages to an ObservableCollection and they appear instantly without refreshing the whole view.

Common follow-ups: Does it notify on item property changes? | What if you replace the collection?

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All 6 Advanced Data Binding & Collections questions