private int GetBorrowInterest(DateTime date) { int borrow = GetBorrow(); Order buyin = ((List <Order>)DBManager.share.GetAllListFromTable(Order.TABLE_NAME, typeof(Order))).Find(x => x.ID == OrderIDs.First()); return((int)(borrow * 0.05 * (new TimeSpan(date.Ticks - buyin.Date.Ticks).TotalDays + 2) / 365)); }