[Bug]: WPF thread error in v24

Author: HakoyuCreated Sep 8, 2026Updated Sep 11, 2026

Labelsbug

Describe the bug

CollectionView of this type does not support changes to its SourceCollection from threads other than the dispatcher thread.

Step to reproduce

Start WPF and trigger WhenAnyValue

csharp

public partial class MainWindow : Window, IViewFor<MainViewModel>
{
    public MainViewModel? ViewModel { get; set; }
    object? IViewFor.ViewModel
    {
        get => ViewModel;
        set => ViewModel = (MainViewModel)value!;
    }

    public MainWindow()
    {
        InitializeComponent();

        RxAppBuilder.CreateReactiveUIBuilder().WithWpf().BuildApp();
        DataContext = ViewModel = new();
        Loaded += MainWindow_Loaded;
    }

    private void MainWindow_Loaded(object sender, RoutedEventArgs e)
    {
        this.Bind(ViewModel, vm => vm.Text, v => v.TextBox.Text);
        this.Bind(ViewModel, vm => vm.Strings, v => v.ListBox.ItemsSource);
    }
}

public class MainViewModel : ReactiveObject
{
    public MainViewModel()
    {
        this.WhenAnyValue(x => x.Text)
            .Throttle(TimeSpan.FromSeconds(1), RxSchedulers.TaskpoolScheduler)
            .Where(x => string.IsNullOrWhiteSpace(x) is false)
            .ObserveOn(RxSchedulers.MainThreadScheduler)
            .Subscribe(x => Strings.Add(x));
    }

    public string Text
    {
        get;
        set => this.RaiseAndSetIfChanged(ref field, value, nameof(Text));
    }

    public ObservableCollection<string> Strings { get; set; } = new();
}