Нумерация элементов ListBox

private void LoadingRow(object sender, DataGridRowEventArgs e)
{
    e.Row.Header = (e.Row.GetIndex() + 1).ToString();
}

        static DataTemplate DefaultTemplate
        {
            get
            {
                string ts = "<DataTemplate xmlns=\"http://schemas.microsoft.com/winfx/2006/xaml/presentation\">" +
                              "<TextBlock Text=\"{ Binding}\" TextAlignment=\"Right\" Background=\"{ Binding Foreground, RelativeSource = { RelativeSource AncestorType = ListBox }}\" Foreground=\"{ Binding Background, RelativeSource = { RelativeSource AncestorType = ListBox }}\" Margin = \" 0, 0.5, 4, 0.5\" Padding = \"1, 0, 1, 0\" />" +
                          "</DataTemplate>";
                return XamlReader.Parse( ts ) as DataTemplate;
            }
        }

        static DataTemplate DefaultTemplate { get; } = XamlReader.Parse
        (
@"<DataTemplate xmlns=""http://schemas.microsoft.com/winfx/2006/xaml/presentation"">
    <TextBlock Text=""{ Binding}""
                TextAlignment=""Right""
                Background=""{Binding Foreground, RelativeSource = {RelativeSource AncestorType=ListBox}}""
                Foreground=""{Binding Background, RelativeSource = {RelativeSource AncestorType=ListBox}}""
                Margin=""0, 0.5, 4, 0.5""
                Padding = ""1, 0, 1, 0"" />
</DataTemplate>"
        ) as DataTemplate;