public IList<Category> GetByParentID(string parentID) { if (string.IsNullOrEmpty(parentID)) { return null; } IList<Category> list = GetAllCache().Where(x => x.ParentID == parentID).Where(e => e.Status > -1).ToList(); if (list == null || list.Count < 1) { using (CategoryDal dal = new CategoryDal()) { list = dal.GetByParentID(parentID); } } return list; }