<Grid>
  <core:C1Button Content="GroupByBorn" Click="OnGroupByBorn" Padding="10 3 10 3"/>
  <core:C1Button Content="GroupByResident" Click="OnGroupByResidence" Margin="30 0 0 0" Padding="10 3 10 3"/>
  <core:C1Button Content="RemoveGrouping" Click="OnRemoveGrouping" Margin="30 0 0 0" Padding="10 3 10 3"/>
  <c1:C1ListView x:Name="listView" DisplayMemberPath="Name" Padding="10 0 0 0" />
</Grid>

public MainWindow()
{
    InitializeComponent();
    //Bind datasource
    listView.ItemsSource = Person.Generate(100);
}
// Add grouping by GroupAysnc method
private async void OnGroupByBorn(object sender, RoutedEventArgs e)
{
    await listView.DataCollection.GroupAsync(nameof(Person.Born));
}
private async void OnGroupByResidence(object sender, RoutedEventArgs e)
{
    await listView.DataCollection.GroupAsync(nameof(Person.Residence));
}
private async void OnRemoveGrouping(object sender, RoutedEventArgs e)
{
    await listView.DataCollection.GroupAsync();
}