public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture) {
if (values.Length != 3) return null;
if (values[0] != null) return ControlsStrings.AcObject_AuthorLabel;
if (values[1] != null) return ControlsStrings.AcObject_VersionLabel;
if (values[2] != null) return ControlsStrings.AcObject_UrlLabel;
return ControlsStrings.AcObject_AuthorLabel;
}