private void AddCategories(string beginDate, string endDate, int categoryID) { List <EtPurchase> tmpLists = new List <EtPurchase>(); ECategory parentCategoryID = (ECategory)categoryID; tmpLists = PurchaseDao.QueryByPurchaseDate(beginDate, endDate, parentCategoryID); ClsCategory category = GetClsCategory(tmpLists); if (category != null) { categories.Add(category); } }