public override int GetHashCode()
        {
            int result = base.GetHashCode();

            result = (result * 397) ^ LibraryId.GetHashCode();
            result = (result * 397) ^ LibraryName.GetHashCode();
            result = (result * 397) ^ LibraryPicture.GetHashCode();
            result = (result * 397) ^ Title.GetHashCode();
            result = (result * 397) ^ Author.GetHashCode();
            result = (result * 397) ^ Isbn.GetHashCode();
            result = (result * 397) ^ PublishYear.GetHashCode();
            return(result);
        }
 public override int GetHashCode()
 {
     return(LibraryName.GetHashCode() ^ DocumentName.GetHashCode());
 }