private void GetEvaluation(HttpContext CurrentContext)
        {
            NewsEvaluationModelBll bll = new NewsEvaluationModelBll();
            int NewsID = Convert.ToInt32(CurrentContext.Request["nid"]);
            if (NewsID == 0)
            {
                CurrentContext.Response.Write(GetJsonResult(false, "参数错误!"));
                return;
            }

            DataTable dt = bll.StatisticList(NewsID);
            int Sum = 0;
            foreach (DataRow row in dt.Rows) Sum += Convert.ToInt32(row["evaluationcount"]);

            StringBuilder result = new StringBuilder();
            StringWriter sw = new StringWriter(result);
            JsonWriter writer = new JsonWriter(sw);
            writer.Formatting = Formatting.Indented;

            writer.WriteStartObject();

            WriteJsonKeyValue(writer, "sum", Sum.ToString());

            writer.WritePropertyName("items");
            writer.WriteStartArray();
            foreach (DataRow row in dt.Rows)
            {
                writer.WriteStartObject();

                WriteJsonKeyValue(writer, "evaluation", row["evaluation"].ToString());
                WriteJsonKeyValue(writer, "count", row["evaluationcount"].ToString());
                WriteJsonKeyValue(writer, "percentage", Sum == 0 ? "0" : Convert.ToDouble((Convert.ToInt32(row["evaluationcount"]) * 100) / Sum).ToString("00"));

                writer.WriteEndObject();
            }
            writer.WriteEndArray();
            writer.WriteEndObject();
            writer.Close();
            CurrentContext.Response.Write("("+result.ToString()+")");
        }