public IEnumerable <Label> SaveLabels(Topic topic, ImageLabel image, IEnumerable <Label> labels)
{
#region validation
if (topic == null)
{
throw new ArgumentNullException(nameof(topic));
}
if (image == null)
{
throw new ArgumentNullException(nameof(image));
}
#endregion
List <Label> result = new List <Label>();
if (labels != null)
{
if (labels.Any())
{
result = LabelRepository.AddOrUpdateOrDeleteLabels(topic, image, labels).ToList();
}
else
{
LabelRepository.DeleteLabels(topic, image);
}
}
return(result);
}