WPF:带有MVVM的SelectAll \ UnSelectAll

public class Item : INotifyPropertyChanged
{
    private bool isSelected;

    public bool IsSelected
    {
        get { return isSelected; }
        set
        {
            if (isSelected != value)
            {
                isSelected = value;
                OnPropertyChanged(nameof(IsSelected));
            }
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    protected virtual void OnPropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

public class MainViewModel
{
    public ObservableCollection<Item> Items { get; } = new ObservableCollection<Item>();

    public void SelectAll()
    {
        foreach (var item in Items)
        {
            item.IsSelected = true;
        }
    }

    public void UnSelectAll()
    {
        foreach (var item in Items)
        {
            item.IsSelected = false;
        }
    }
}

<Window x:Class="YourNamespace.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:YourNamespace"
        Title="WPF with MVVM SelectAll/UnSelectAll" Height="450" Width="800">
    <Grid>
        <ListBox ItemsSource="{Binding Items}">
            <ListBox.ItemContainerStyle>
                <Style TargetType="ListBoxItem">
                    <Setter Property="IsSelected" Value="{Binding IsSelected}"/>
                </Style>
            </ListBox.ItemContainerStyle>
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <TextBlock Text="{Binding YourDataProperty}"/>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
    </Grid>
</Window>