Uncaught TypeError: Cannot read property 'length' of undefined

ironcurtain

Hi All. I searched everyware but with no success trying to fix the error. I want to use server side processing to display large (over 4000 records) data from database. I'm using ASP MVC and EF. Here is my code:

    public JsonResult HostsJSON()
    {
        IEnumerable<vw_Host> lst_Host_DB;
        lst_Host_DB = Host.GetAllActive();

        var result = Json(lst_Host_DB, JsonRequestBehavior.AllowGet);

        return result;        
}

   <script type="text/javascript">
$(document).ready(function () {
    applyFullDatatable('#tblHosts');

    var columnsExport = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25]
    function applyFullDatatable(tableholder) {
        $(tableholder).DataTable({
            dom: 'l<Bf>tip',
            scrollX: true,
            lengthMenu: [[10, 25, 50, 100, -1], [10, 25, 50, 100, "All"]],
            scrollY: 440,
            scrollCollapse: true,
            bSortClasses: false,                
            ajax: {
                url: "@(Url.RouteUrl("HostsJSON"))",
                type: "POST"
            },
            buttons: [
                {
                    extend: 'copy',
                    text: 'Copy to clipboard',
                    exportOptions: {
                        columns: columnsExport
                    }
                },
                {
                    extend: 'csv',
                    text: 'Export to CSV',
                    title: 'Hosts',
                    exportOptions: {
                        columns: columnsExport
                    }
                },
                {
                    extend: 'excel',
                    text: 'Export to XLSX',
                    title: 'Hosts',
                    exportOptions: {
                        columns: columnsExport
                    }
                }
            ]
        });
    };
});

</script>

allan

Thanks for your question - however, per the forum rules can you link to a test case showing the issue please. This will allow the issue to be debugged.

Information on how to create a test page, if you can't provide a link to your own page can be found here.

Thanks,
Allan

ironcurtain

Hi allan. Thank you for your reply. Unfortunately I can't post the page there. On the other hand I found that when I added line:

dataSrc: ""

error changed to:

DataTables warning: table id=tblHosts - Requested unknown parameter '0' for row 0, column 0. For more information about this error, please see http://datatables.net/tn/4

In my Controller I am returing IDs which are not in HTML. Do you think the issue is related the the columns mapping? On my HTML page I am displaying fields without IDs.
Please let me know if my explanations are not clear.

allan

Can you show me the Ajax it is returning. If a link can't be given, can you use the debugger please.

Allan

ironcurtain

Hi allan - I made some progress. I've added below code:

columns: [
{ "data": "SystemName" },
{ "data": "ApplicationName" },
{ "data": "Hostname" }
],

and it started to work. My question is - why search option is not working? I mean when I type something in search box the table is not filtered. Additionally record count is showing:

Showing 0 to 0 of 0 entries

Is it necessary to put these lines:

columns: [
{ "data": "SystemName" },
{ "data": "ApplicationName" },
{ "data": "Hostname" }
],

It is additional thing that has to be maintained and I would like to control the columns from model.

I also tested this and it works when amount of rows is about 1000. When I am trying do display about 2000 records below error occurred:

DataTables warning: table id=tblHosts - Ajax error. For more information about this error, please see http://datatables.net/tn/7 - Failed to load resource: the server responded with a status of 500 (Internal Server Error)

allan

My question is - why search option is not working?

I'm afraid I don't know - I'd need more information such as that offered by the debugger.

For a 500 internal error you would need to refer to your server's error log to see what error message is being reported there.

Allan