Why do I get one int[] element that is 0 in controller and null is sent from ajax call?

Question

When a form contains no selected items, it creates me a table with one ite that is 0, how to remove it elegantly? where?

JS :

$(document).on('click', '#submitButton', function () {
                showLoader();
                $.ajax({
                    url: "@Url.Action("Search", "Home")",
                    cache: false,
                    type: "POST",
                    dataType: "html",
                    traditional: true,
                    data: { secteurs: $("#secteursDiffusion").val(), auditeurs: $("#auditeursDiffusion").val(), audites: $("#auditesDiffusion").val(), services: $("#servicesDiffusion").val() },
                    success: function (result) {
                        $("#resultPlaceholder").html(result);
                    }
                });
            });

At this point, when I evaluate in console $("#secteursDiffusion").val() for instance, I can see items that were selected in $("#secteursDiffusion"), OK (result:["676"]) ! And when I evaluate $("#auditesDiffusion").val() in console, this is null (result:null), so all is OK.

In the controller:

public ActionResult Search(int[] secteurs, int[] auditeurs, int[] audites, int[] services)
        {   ...   }

when I breakpoint in the controller, I received audites (that were evaluated in console as null) with one item that is 0, why? And how remve it elegantly?

Thanks in advance

EDIT:

HTML Code of one input:

<select data-placeholder="Ajoutez un ou plusieurs secteurs" id="secteursDiffusion" multiple="multiple" name="secteursDiffusion">
<option value="992379">item55</option>
<option value="993147">item56</option>
<option value="996096">item57</option>
<option value="33033095">item58</option>
</select>

EDIT2: with int?[] Same problem:

Answer 1

Although the value is null you are still passing some value for audites . As it is not an array, MVC thinks you are passing an int value and so sets it to its default value - 0 (as Stephen pointed out, this is the behaviour of the DefaultModelBinder ).

You need to ensure an array is passed, so if it is null , send [] instead - note that audites then becomes null in the controller action, rather than an empty array, but that makes more sense than [0] :

$(document).on('click', '#submitButton', function () {
    showLoader();
    $.ajax({
        url: "@Url.Action("Search", "Home")",
        cache: false,
        type: "POST",
        dataType: "html",
        traditional: true,
        data: {
            secteurs: $("#secteursDiffusion").val() || [],
            auditeurs: $("#auditeursDiffusion").val() || [],
            audites: $("#auditesDiffusion").val() || [],
            services: $("#servicesDiffusion").val() || []
        },
        success: function (result) {
            $("#resultPlaceholder").html(result);
        }
    });
});