private void queryPieReport()
        {
            String curDate  = "2013-01-01";
            var    curYear  = DateTime.Parse(curDate).Year.ToString();
            var    lastYear = DateTime.Parse(curDate).AddYears(-1).Year.ToString();
            var    master   = new CategorySalesReportByYear();

            categoryReportByYear = _reportService.RetrieveCategorySalesReportByYear(master, curYear, lastYear);
            //转换json
            String categorys = JsonConvert.SerializeObject(categoryReportByYear.SalesReportByCategory
                                                           .Select(x => x.ProductCategoryName));

            String categorysData = JsonConvert.SerializeObject(categoryReportByYear.SalesReportByCategory
                                                               .Select(x => new
            {
                name = x.ProductCategoryName, value = x.TotalSalesqty
            }));

            categoryReportByYear.Json_Categorys     = categorys;
            categoryReportByYear.Json_categorysData = categorysData;
        }