MultiLevel Grouping in ListView

The SfListView supports multiple level grouping by adding multiple GroupDescriptor objects into the DataSource.GroupDescriptors collection. The grouped items will be displayed in hierarchical structure by customizing the SfListView.GroupHeaderTemplate property. In the GroupHeaderTemplate, set the Padding property to the custom view to arrange the group header items and sub-group header items in the hierarchical structure.

<ContentPage xmlns:syncfusion="clr-namespace:Syncfusion.ListView.XForms;assembly=Syncfusion.SfListView.XForms"
             xmlns:data="clr-namespace:Syncfusion.DataSource;assembly=Syncfusion.DataSource.Portable">
  <ContentPage.Resources>
    <ResourceDictionary>
      <local:GroupHeaderConverter x:Key="TemplateConverter"/>
    </ResourceDictionary>
  </ContentPage.Resources>
  <syncfusion:SfListView ItemsSource="{Binding EmployeeInfo}" ItemSize="60">
    <syncfusion:SfListView.DataSource>
      <data:DataSource>
        <data:DataSource.GroupDescriptors>
            <data:GroupDescriptor PropertyName="Designation" />
            <data:GroupDescriptor PropertyName="Level" />
        </data:DataSource.GroupDescriptors>
      </data:DataSource>
    </syncfusion:SfListView.DataSource>
    <syncfusion:SfListView.GroupHeaderTemplate>
      <DataTemplate>
          <ViewCell>
            <ViewCell.View>
              <StackLayout BackgroundColor="{Binding Level,Converter={StaticResource TemplateConverter}}"
                            Padding="{Binding Level,Converter={StaticResource TemplateConverter}}">
                  <Label Text="{Binding Key}" 
                        VerticalOptions="Center" HorizontalOptions="Start"/>
              </StackLayout>
            </ViewCell.View>
          </ViewCell>
      </DataTemplate>
    </syncfusion:SfListView.GroupHeaderTemplate>
  </syncfusion:SfListView>
</ContentPage>

listView.ItemsSource = viewModel.EmployeeInfo;
listView.ItemSize = 60;
listView.DataSource.GroupDescriptors.Add(new GroupDescriptor()
{
  PropertyName = "Designation",
});
listView.DataSource.GroupDescriptors.Add(new GroupDescriptor()
{
  PropertyName = "Designation",
});
listView.GroupHeaderTemplate = new DataTemplate(() =>
{
  var stack = new StackLayout();
  Binding binding = new Binding("Level");
  binding.Converter = new TemplateConverter();
  stack.SetBinding(StackLayout.BackgroundColorProperty, binding);
  stack.SetBinding(StackLayout.PaddingProperty, binding);

  var label = new Label() { VerticalOptions=LayoutOptions.Center,HorizontalOptions=LayoutOptions.Start};
  label.SetBinding(Label.TextProperty, new Binding("Key"));

  return stack;
});

public class GroupHeaderConverter : IValueConverter
{
  public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
  {
     if (targetType.Name == "Color")
     {
        if ((int)value == 1)
           return Color.FromHex("#D3D3D3");
        else
           return Color.Transparent;
     }
     else
     {
        if ((int)value == 1)
           return new Thickness(5, 5, 5, 0);
        else
           return new Thickness((int)value * 15, 5, 5, 0);
     }
  }

   public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
   {
     throw new NotImplementedException();
   }
}

To know more about grouping in ListView, please refer our documentation here.