导出按钮未显示在dataTable中

Question

我进行了ajax调用来获取动态数据，其中标头不固定显示多少列，以以下格式获取数据后，无法导出或限制行数，标头可以超过30个。 任何帮助将不胜感激。

这是我的html代码：

                    <div class="table-responsive" id="live_tracking_table_cantainer">
                        <table class="table table-striped table-bordered dataTable livertrackingtable">

                        </table>
                    </div>




Ajax call : 

    $(".livetracking").click(function () {
        var data = $("#livetrackingform").serialize();
        $.ajax({
            type: 'post',
            url: '/getcampaigndata',
            data: data,
            success: function (dataSet) {
                if (dataSet == '' || dataSet == 'undefined') {
                    $("#live_tracking_table_cantainer").css('text-align', 'center');
                    $("#live_tracking_table_cantainer").html('No data found');
                    return;
                }

                var my_columns = [];
                $.each(dataSet[0], function (key, value) {
                    var my_item = {};
                    my_item.data = key;
                    my_item.title = key;
                    my_columns.push(my_item);
                });

                $('#live_tracking_table_cantainer').empty();
                $table = $('<table style="width: 100%">');
                $table.addClass("table table-striped table-bordered dataTable livertrackingtable");
                $($table).DataTable({
                    data: dataSet,
                    "columns": my_columns,
                    "order": [],
                    "columnDefs": [{
                        "targets": 'no-sort',
                        "orderable": false,
                    }],
                    "aLengthMenu": [[10, 25, 50, -1], [10, 25, 50, "All"]],
                    dom: 'Bfrtip',
                    buttons: [
                        'copy', 'csv', 'excel', 'pdf', 'print'
                    ]
                });
                $table.appendTo('#live_tracking_table_cantainer');

            },
            error: function (data) {
                console.log(data);
            }
        });
    });

What I am getting from ajax call : 

[{created_at: "23-04-2019 05:22 PM", Name: "Test", Designation: "ZSM", Zone: "North", Region: "",…},…]
0: {created_at: "23-04-2019 05:22 PM", Name: "Test", Designation: "ZSM", Zone: "North", Region: "",…}
1: {created_at: "23-04-2019 05:28 PM", Name: "Test", Designation: "ZSM", Zone: "North", Region: "",…}
2: {created_at: "23-04-2019 05:30 PM", Name: "Test", Designation: "ZSM", Zone: "North", Region: "",…}
3: {created_at: "25-04-2019 05:24 PM", Name: "Test", Designation: "ZSM", Zone: "North", Region: "",…}
4: {created_at: "29-04-2019 06:23 PM", Name: "Test", Designation: "ZSM", Zone: "North", Region: "",…}
5: {created_at: "29-04-2019 06:24 PM", Name: "Test", Designation: "ZSM", Zone: "North", Region: "",…}