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);
}
}