wpf listview's selectionchanged is fired but the command is not fired.

[CodingOctocat]

Mini demo:

Win11 + .NET 7.0

• CommunityToolkit.Mvvm Version="8.2.0"
• Microsoft.Xaml.Behaviors.Wpf Version="1.1.39"

<Window x:Class="ListViewSelectionChangedCommandNotFired.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:b="http://schemas.microsoft.com/xaml/behaviors"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:local="clr-namespace:ListViewSelectionChangedCommandNotFired"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        Title="MainWindow"
        Width="800"
        Height="450"
        d:DataContext="{d:DesignInstance Type=local:MainWindow,
                                         IsDesignTimeCreatable=True}"
        DataContext="{Binding Mode=OneWay, RelativeSource={RelativeSource Self}}"
        FontSize="16"
        Loaded="Window_Loaded"
        mc:Ignorable="d">
    <UniformGrid Rows="1">
        <ListView ItemsSource="{Binding DataList}"
                  SelectedItem="{Binding SelectedItem, Mode=TwoWay}"
                  SelectionChanged="ListView_SelectionChanged">
            <b:Interaction.Triggers>
                <b:EventTrigger EventName="SelectionChanged">
                    <b:InvokeCommandAction Command="{Binding SelectionChangedCommand}" />
                </b:EventTrigger>
            </b:Interaction.Triggers>
        </ListView>

        <TextBox x:Name="Output" />
    </UniformGrid>
</Window>

using System.Collections.ObjectModel;
using System.Windows;

using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;

namespace ListViewSelectionChangedCommandNotFired;

/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
[INotifyPropertyChanged]
public partial class MainWindow : Window
{
    [ObservableProperty]
    private string? _selectedItem;

    public MainWindow()
    {
        InitializeComponent();
    }

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

    private void ListView_SelectionChanged(object sender, System.Windows.Controls.SelectionChangedEventArgs e)
    {
        Output.Text += "SelectionChanged Event fired!\n";
    }

    [RelayCommand]
    private void SelectionChanged()
    {
        Output.Text += "SelectionChanged Command fired!\n";
    }

    private void Window_Loaded(object sender, RoutedEventArgs e)
    {
        DataList.Add("Sample data 1");
        SelectedItem = DataList[^1];

        DataList.Add("Sample data 2");
        SelectedItem = DataList[^1];

        DataList.Add("Sample data 3");
        SelectedItem = DataList[^1];
    }
}

[michael-hawker]

@CodingOctocat the Wpf Behaviors are in another repo: https://github.com/microsoft/XamlBehaviorsWpf

@mgoertz-msft maybe should add issue templates here to have a link to point to that repo called out?