Why is my CollectionView not updating when data changes?

The bound collection must be an ObservableCollection (or raise CollectionChanged), and items must raise PropertyChanged for their own field updates. Reassigning a plain List won't refresh unless the holding property notifies. Also ensure updates happen on the UI thread.

// Won't refresh:
Items = new List<Item>(newData);
// Will refresh:
public ObservableCollection<Item> Items { get; } = new();
Items.Clear(); foreach (var i in newData) Items.Add(i);