Как обрабатывать ItemClick для вложенного ListView в шаблоне MVVM?

Для вложенного ListViewItemClick в шаблоне MVVM вы можете использовать Xaml-поведения SDK, чтобы добавить событие ItemClick, как показано ниже.

<ListView Name = "HeaderList"  ItemsSource = "{Binding Items}" >
    <ListView.ItemTemplate>
        <DataTemplate>
            <Grid>
                <Border Background = "Bisque">
                    <TextBlock Text = "{Binding Test}"/>
                </Border>

                <ListView Name = "SubItemsList" ItemsSource = "{Binding SubItems}" 
                           IsItemClickEnabled = "True" 
                           SelectedItem = "{Binding SelectItme,Mode=TwoWay}" >
                    <ListView.ItemTemplate>
                        <DataTemplate>
                            <StackPanel Orientation = "Vertical">
                                <TextBlock Text = "{Binding }"/>
                            </StackPanel>
                        </DataTemplate>
                    </ListView.ItemTemplate>

                    <i:Interaction.Behaviors >
                        <ic:EventTriggerBehavior  EventName = "ItemClick">
                            <ic:InvokeCommandAction  Command = "{Binding ItemCommand}" 
                                                     CommandParameter = "{Binding}" />
                        </ic:EventTriggerBehavior>
                    </i:Interaction.Behaviors>
                </ListView>
            </Grid>
        </DataTemplate>
    </ListView.ItemTemplate>
</ListView>

И вам нужно добавить SelectedItem = "{Binding SelectItme,Mode=TwoWay}", который используется для определения того, какой элемент вы выбрали.

ViewModel

class TestViewModel
{
    public class Item : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;
        public void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
        public string Test { get; set; }
        public ObservableCollection<string> SubItems { get; set; }

        private string _selectItme;

        public string SelectItme
        {
            get
            {
                return _selectItme;
            }
            set
            {
                _selectItme = value;
                OnPropertyChanged();
            }
        }
        public Item()
        {
            SubItems = new ObservableCollection<string>() { "zhuzhu", "heheh", "liuliu", "momo" };
        }

        public ICommand ItemCommand
        {
            get
            {
                return new CommadEventHandler<object>((item) => ItemClick(item));
            }
        }
        private void ItemClick(object item)
        {
            System.Diagnostics.Debug.WriteLine("--------------------");
        }
    }

    public ObservableCollection<Item> Items { get; set; }

    public TestViewModel()
    {
        Items = new ObservableCollection<Item>();

        Items.Add(new Item { Test = "Item 1" });
        Items.Add(new Item { Test = "Item 2" });
        Items.Add(new Item { Test = "Item 3" });
        Items.Add(new Item { Test = "Item 4" });
        Items.Add(new Item { Test = "Item 5" });
        Items.Add(new Item { Test = "Item 7" });
        Items.Add(new Item { Test = "Item 8" });
        Items.Add(new Item { Test = "Item 9" });
        Items.Add(new Item { Test = "Item 10" });
        Items.Add(new Item { Test = "Item 11" });
    }

}

class CommadEventHandler<T> : ICommand
{
    public event EventHandler CanExecuteChanged;

    public Action<T> action;
    public bool CanExecute(object parameter)
    {
        return true;
    }

    public void Execute(object parameter)
    {
        this.action((T)parameter);
    }
    public CommadEventHandler(Action<T> action)
    {
        this.action = action;

    }
}