public void RemoveContents(IEnumerable <int> ids, UserIdentity userIdentity)
{
var contentsToRemove = ContentBiz.Read(a => ids.Contains(a.Id) && a.AuthorId == userIdentity.UserId);
HashSet <string> pictureNamesToRemove = new HashSet <string>();
foreach (var content in contentsToRemove)
{
ContentBiz.Remove(content);
}
UnitOfWork.SaveChanges();
}