无法读取属性'_data 'of undefined(…)-数据表

我正试图从datatable的单元格中读取data()，其中有一个按钮在里面，但我得到了一个错误。

这是我的Datatable定义:

$("#example").DataTable({
                destroy: true,
                "columnDefs": [{
                    orderable: false,
                    targets: 0
                }],
                "columns": [
                    {
                        "data": "slno",
                        "fnCreatedCell": function (nTd, sData, oData, iRow, iCol) {
                            $(nTd).html('<a href="AddNewTicket.aspx?subjectID=' + oData.subjectID + '&subject_id=' + oData.subject_id + '&serviceID=' + oData.crm_services_id + '&severityID=' + oData.severityID + '&statusID=' + oData.statusID + '&callerID=' + '66355356' + '">' + oData.slno + '</a>');
                        },
                    },
                    { "data": "status_message" },
                    { "data": "crm_services_id" },
                    { "data": "subject_id" },
                    { "data": "severity_id" },
                    {"data": "user_id" },
                    { "data": "status_id" },
                    {
                        "data": "caller_number",
                        "fnCreatedCell": function (nTd, sData, oData, iRow, iCol) {
                            $(nTd).html('<button class="btn btn-primary" id= "' + oData.subjectID + '">Call Customer</button>');
                        },
                    }
                ],
                select: {
                    style: 'os',
                    selector: 'td:first-child'
                },
                "data": response,
                "sDom": '<"top">tip'
            });

这里是我试图获取数据的地方:

var table = $("#example").DataTable();
        $('#example tbody').on('click', 'button', function () {
            var subjectID = $(this).attr('id');
            var thisData = table.row($(this).parents('tr')).data();
            var userID = thisData[7];
            sendCallRequest(subjectID, userID);
        });

下面是我得到的错误:

无法读取未定义的属性'_aData'(…)

有什么建议吗?

var table = $("#example").DataTable();
    $('#example tbody').off('click');
    $('#example tbody').on('click', 'button', function () {
        var subjectID = $(this).attr('id');
        var thisData = table.row($(this).parents('tr')).data();
        var userID = thisData[7];
        sendCallRequest(subjectID, userID);
    });