มีปัญหาเกี่ยวกับการแสดงข้อมูลใน pie chart จาก sql server asp.net c#

    private void GetPieChartByJava(DataTable dt)
    {
        string _String = "";

        _String += "<script type='text/javascript'>";
        _String += "$(function () {";
        _String += "    $('#container').highcharts({";
        _String += "        chart: {";
        _String += "            plotBackgroundColor: null,";
        _String += "            plotBorderWidth: null,";
        _String += "            plotShadow: false,";
        _String += "            type: 'pie'";
        _String += "        },";
        _String += "        title: {";
        _String += "            text: 'Data Get Jobnumber'";
        _String += "        },";
        _String += "        tooltip: {";
        _String += "            pointFormat: '{series.name}: <b>{point.percentage:.1f}%</b>'";
        _String += "        },";
        _String += "        plotOptions: {";
        _String += "            pie: {";
        _String += "                allowPointSelect: true,";
        _String += "                cursor: 'pointer',";
        _String += "                dataLabels: {";
        _String += "                    enabled: true,";
        _String += "                    format: '<b>{point.name}</b>: {point.percentage:.1f} %',";
        _String += "                    style: {";
        _String += "                        color: (Highcharts.theme && Highcharts.theme.contrastTextColor) || 'black'";
        _String += "                    }";
        _String += "                }";
        _String += "            }";
        _String += "        },";
        _String += "        series: [{";
        _String += "            name: 'Jobnumber',";
        _String += "            colorByPoint: true,";


        _String += "            data: [";
        for (int i = 0; i < dt.Rows.Count; i++)
        {

            _String += "{ name:'" + dt.Rows[i]["Jobnumber"].ToString() + "', y: " + dt.Rows[i]["Qty"].ToString() + "}";
            if ((i == 0 && dt.Rows.Count > 0) || (i > 0 && i < dt.Rows.Count))
            {
                _String += ",";
            }
        }

        _String = _String.Remove(_String.Length - 1);

        _String += "            ]";
        _String += "        }]";
        _String += "    });";
        _String += "});";

        _String += "</script>";
        chrtMyChart_PieJava.Text = _String.ToString();

    }