using System.Collections.ObjectModel; using System.Linq; using ReactiveUI; namespace ControlCatalog.ViewModels { public class ItemsRepeaterPageViewModel : ReactiveObject { private int newItemIndex = 1; public ItemsRepeaterPageViewModel() { Items = new ObservableCollection( Enumerable.Range(1, 100000).Select(i => $"Item {i}")); } public ObservableCollection Items { get; } public void AddItem() { Items.Insert(0, $"New Item {newItemIndex++}"); } } }