CODEWITHSUNDEEP
javascriptjqueryajaxasp.net-mvc
Davide Vitali
Davide Vitali

Reputation: 1035

empty response from a jquery ajax over an mvc action method

I have an inventory application in a layout like this:

<body>
<div class="container" style="width: 100%">
        <div id="header"> blahblahblah </div>
        <div class="row">
            <div id="rendermenu" class="col-sm-2">
                @Html.Action("Menu", "Nav")
            </div>
            <div id="renderbody" class="col-sm-10">
                @RenderBody()
            </div>
    </div>
</div>

In the Home controller there is an action method that filters the repository sent to the view:

public ActionResult Index(string categoria, string marca)
{
    InventarioViewModel viewModel = new InventarioViewModel
    {
        Inventario = repository.GetInventario()
            .Where(i => (categoria == null || i.Item.Categoria == categoria)
                     && (marca == null || i.Item.Marca == marca))
            .OrderBy(i => i.Qta > 0)
            .ThenBy(i => i.Item.Categoria)
            .ThenBy(i => i.Item.Marca)
            .ThenBy(i => i.Item.Modello).ToList(),
        CategoriaCorrente = categoria,
        MarcaCorrente = marca
    };

    return View(viewModel);
}

It works fine, but only by typing the desired route in the browser. So I started writing a filter by putting a <select> element that presents the user the items categories, then binding an AJAX call to its change event. This is the markup for the menu view:

@using Magazzino.Domain.Infrastructure
@using Magazzino.Domain.Entities
@model List<Item>

@{ IEnumerable<Item> items = Model.DistinctBy(x => x.Categoria); }

<div class="text-center">Filtra per:</div>
<hr />
<div class="text-center">Categoria</div>
<select class="form-control lista-categorie" id="lista-categorie" data-action-url="@Url.Action("Index", "Home")" name="categoria">
    <option value>-- seleziona --</option>
    @foreach (Item item in items)
    {
        <option value="@item.Categoria">@item.Categoria</option>
    }
</select>

This is the AJAX call, put inside the usual $(document).ready(...):

$('#lista-categorie').on('change', function () {
    var e = $(this)[0];
    if (e.selectedIndex > 0) {
        var ajaxRequest = $.ajax({
            url: "/",
            type: "get",
            data: {
                categoria: e.options[e.selectedIndex].value,
                marca: null
            }
        })

        ajaxRequest.done(function (response) {
            $('#renderbody').html(response);
        });
    }
});

I also changed part of the controller where the view is rendered:

if (Request.IsAjaxRequest())
{
    return PartialView(viewModel);
}
else
{
    return View(viewModel);
}

but I get just an empty string. If try to get the full view, I see that the response has the whole page (layout and menu) BUT the Index view:

// previous markups from layout and menu
        <div id="renderbody" class="col-sm-10">




        </div>
    </div>
</div>

// other markups

I'm sure the Index action method is triggered because I put a breakpoint. Though, the moment I change the AJAX call itself this way, it works fine:

var ajaxRequest = $.ajax({
            url: "/" + e.options[e.selectedIndex].value,
            type: "get"
        })

but I don't really like this workaround, I'd like to have a more plain, efficient way of passing data to the controller.

How can I change this behaviour?

Upvotes: 0

Views: 514

Answers (2)

Iason
Iason

Reputation: 382

$('#lista-categorie').on('change',method_attached_to_event);

function method_attached_to_event(){

  var e = $(this)[0];
  if (e.selectedIndex > 0) {

    var url = '/';
    var obj = {};
    obj.categoria= e.options[e.selectedIndex].value;

    $.ajax({
      url:url,
      method:'POST',
      data:obj,
      success:success,
      error:error
    }); 

  }else{
    // Do something else
  }
}

function success(data,status,jqxhr){
   console.log(data);
}

function error( jqxhr, status, error ){
   console.log(status);
   console.log(error);
   console.log(jqxhr);
}

Upvotes: 0

Davide Vitali
Davide Vitali

Reputation: 1035

TOTALLY my bad: I re-edited the question because when I said "I'm sure the ViewModel get populated", it was true-ish. I only checked that the action method was triggered.

I have now checked the ViewModel and found the problem: I didn't take into account that the "null" value sent by the AJAX call isn't actually null, but an empty string. I have changed the LINQ expression accordingly and it works

InventarioViewModel viewModel = new InventarioViewModel
{
    Inventario = repository.GetInventario()
        .Where(i => (string.IsNullOrEmpty(categoria) || i.Item.Categoria == categoria) 
                 && (string.IsNullOrEmpty(marca) || i.Item.Marca == marca))
        .OrderBy(i => i.Qta > 0)
        .ThenBy(i => i.Item.Categoria)
        .ThenBy(i => i.Item.Marca)
        .ThenBy(i => i.Item.Modello).ToList(),
    CategoriaCorrente = categoria,
    MarcaCorrente = marca
};

Despite being a trivial bug (and an incredibly embarassing moment), I'd like to answer my own question and keep it for those who might face the same problem.

Cheers.

Upvotes: 1

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