WinUI 3 Desktop - Binding does not work

In WinUI 3 Preview 1 Desktop - Binding markup extensions are not working correctly in some cases (see comments in XAML). Mode OneWay should be implicit, and all bellow mentioned bindings should work properly.

Steps to reproduce the bug

  <StackPanel>
    <!--  MyTextBox1 x:Bindng works. Text is updated from VM  -->
    <TextBox x:Name="MyTextBox1" Text="{x:Bind ViewModel.NewProductName, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
    <!--  MyTextBox2 Binding does not work. Text is not updated from VM  -->
    <TextBox x:Name="MyTextBox2" Text="{Binding ViewModel.NewProductName, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

    <!--  Command x:Bind works  -->
    <Button Command="{x:Bind ViewModel.AddNew}" Content="Add (works)" />
    <!--  Command Binding does not work  -->
    <Button Command="{Binding ViewModel.AddNew, Mode=OneWay}" Content="Add (does not work)" />

    <!--  Command Binding on nested property does not work  -->
    <Button Padding="5"
            Command="{Binding ViewModel.ListViewModel.ClearFilter, Mode=OneWay}"
            Content="Reset" />
    <!--  Command x:Bind on nested property does not work without Mode  -->
    <Button Command="{x:Bind ViewModel.ListViewModel.ClearFilter}" Content="xBindWithoutMode" />
    <!--  Command x:Bind on nested property works with explicit Mode OneWay.  -->
    <Button Command="{x:Bind ViewModel.ListViewModel.ClearFilter, Mode=OneWay}" Content="xBindWithOneWayMode" />
  </StackPanel>

  public sealed partial class ProductsView : UserControl
  {
    public ProductsView()
    {
      this.InitializeComponent();

      var productsEntityChangesViewModel = App.Kernel.Get<ProductsEntityChangesViewModel>();

      ViewModel = productsEntityChangesViewModel;
    }

    public static readonly DependencyProperty ViewModelProperty = DependencyProperty.Register(nameof(ViewModel), typeof(ProductsEntityChangesViewModel), typeof(ProductsView), new PropertyMetadata(null));

    public ProductsEntityChangesViewModel ViewModel
    {
      get { return GetValue(ViewModelProperty) as ProductsEntityChangesViewModel; }
      set { SetValue(ViewModelProperty, value); }
    }
  }

NuGet package version: [Microsoft.WinUI 3.0.0-preview1.200515.3]

Device form factor	Saw the problem?
Desktop	Yes
Mobile
Xbox
Surface Hub
IoT

[Ratcha9]

My experience is that legacy bindings do not update the target property, when the the PropertyChanged event is raised, regardless of setting the DataContext property or not.

@StephenLPeters {Binding} still doesn’t work for me. The initial value is correct, but it does not update. You may examine https://github.com/Ratcha9/winui_inpc.

[tomasfabian]

@StephenLPeters I think that the “UWP” x:Bind works correctly in case that OneTime is the default mode (chosen for performance reasons). I didn’t have experience with x:Bind. We all should realize that we are coming from different target frameworks. I’m a big fan of unification… so I’m super excited…

I still think that the “classical” Bindings are not working correcly.