Xaml 如果observablecollection为null，如何隐藏Textblock

如果绑定observablecollection包含空，是否可以使用xaml代码隐藏TextBlock？

xaml

<TextBlock Visibility="{Binding ElementName=Labour,Path=Items.Count, Converter={StaticResource ZeroToVisibilityConverter}}" TextWrapping="Wrap" Text="There is no data on this date" Margin="314,200,0,0" FontFamily="Arial" FontSize="14" Height="37" VerticalAlignment="Top" HorizontalAlignment="Left" Width="188"/>

public class ZeroToVisibilityConverter : IValueConverter
{
    #region Implementation of IValueConverter

    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return int.Parse(value.ToString()) == 0 ? Visibility.Visible : Visibility.Collapsed;
    }

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

    #endregion
}