Why sending JSON data via POST (ajax) returns null parameter? - ajax

Question

Good afternoon everybody :)
I am working on asp.net mvc application.
I am using JQuery DataTable in order to show my data.
Actually, my ajax Post request calls a controller method which has to receive some parameters.
The problem is that they are null. I also have the Post 500 error :(
Here is my class:
public class ClientSelectionFiltersViewModel
{
public bool StrictFilteringContractTypes { get; set; }
public string ContractTypes { get; set; }
public string PaymentChoices { get; set; }
public string PopulationTypes { get; set; }
}
Here is a part of cshtml view:
#model ClientSelectionViewModel
#{
ViewBag.Title = "Sélection des clients";
}
<link href="~/lib/datatables/css/dataTables.bootstrap4.min.css" rel="stylesheet" />
<h3><i class="fas fa-clipboard-list mr-3"></i> Sélection des clients</h3>
<div asp-validation-summary="All" class="text-danger mt-2"></div>
<div id="filters">
<form method="post" asp-action="facturationWithFilters">
<!--some code here-->...
</form>
<button id="btn-filter-clients" class="btn atmb-btn-blue"><i class="fas fa-filter fa-fw mr-2"></i>Filtrer les clients</button>
</div>
<div id="client-selection" class="mt-2">
<div class="mb-1">
<a id="btn-send-selection" class="btn float-right atmb-btn-red">
<i class="fas fa-feather-alt fa-fw mr-2"></i>Lancer la facturation pour les utilisateurs sélectionnés
</a>
</div>
<table class="table table-striped table-hover table-sm table-bordered"
id="tableServerSide"
style="width:100%;">
<thead class="thead-dark text-white">
<tr>
<th>Cocher</th>
<th>#</th>
<th>Numéro de client</th>
<th>Types de contrats</th>
<th>Moyen de paiement</th>
<th>Population</th>
</tr>
</thead>
<tbody>
</tbody>
</table>
</div>
#section Scripts {
<!--scripts DataTable-->
<script src="~/js/modal.js"></script>
<script src="~/lib/datatables/js/jquery.dataTables.min.js"></script>
<script src="~/lib/datatables/js/dataTables.bootstrap4.min.js"></script>
<!--script pour la gestion de DataTable-->
<script type="text/javascript">
$('#btn-filter-clients').click(function () {
console.log($("#contractFilter").val()); //ok I get my values
console.log($("#paymentFilter").val()); //ok I get my values
console.log($("#populationFilter").val()); //ok I get my values
console.log("début Data Table");
$("#tableServerSide").DataTable({
"processing": true,
"serverSide": true,
"filter": true,
"ajax": {
"url": "/clientselection/ajaxpostcall",
"type": "POST",
"datatype": "json",
"data": JSON.stringify({
filters: {
"ContractTypes": $("#contractFilter").val(),
"PaymentChoices": $("#paymentFilter").val(),
"PopulationTypes": $("#populationFilter").val(),
"StrictFilteringContractTypes": $("#StrictFilteringContractTypes").is(":checked")
}
}),
"contentType": "application/json",
"success": function (response) {
if (response != null) {
alert("Name : " + response.Name + ", Designation : " + response.Designation + ", Location :" + response.Location);
} else {
alert("Something went wrong");
}
},
"failure": function (response) {
alert(response.responseText);
},
"error": function (response) {
alert(response.responseText);
}
},
"columns": [ // on définit les colonnes du tableau
{
//Cases cocher
"data": null,
"className": "col-checkbox",
"render": function (data, type, row) {
var checkId = 'check' + row.id;
var isChecked = selectedIds.includes(checkId) ? ' checked="checked"' : '';
var checkbox = '<input id="' + checkId + '" type="checkbox" '
+ isChecked
+ ' class="server-checkbox" /> ';
/*
<td class="col-checkbox sorting_1">
<input id="check0" type="checkbox" class="server-checkbox">
</td>
*/
return checkbox;
}
},
{
//Numéro de client
"data": "id",
"className": "col-id"
},
{
//Types de contrats
"data": "contractstypes",
"className": "col-contractstypes",
"render": function (data, type, row) {
var chaine = string.Join(", ", row.value);
return chaine;
}
},
{
//Moyen de paiement PaymentChoice
"data": "paymentchoice",
"className": "col-paymentchoice"
},
{
//Population PopulationType
"data": "populationtype",
"className": "col-populationtype"
}
]
});
});
</script>
}
Here is my controller method:
[HttpPost]
public async Task<JsonResult> AjaxPostCall(ClientSelectionFiltersViewModel filters)
{
//some code here....
return Json(result);
}
I red at least 6 solutions which didn't work for me such as :
in ajax:
"data": JSON.stringify({
filters: {
ContractTypes: $("#contractFilter").val(),
PaymentChoices: $("#paymentFilter").val(),
PopulationTypes: $("#populationFilter").val(),
StrictFilteringContractTypes: $("#StrictFilteringContractTypes").is(":checked")
}
}),
and then in the controller :
[HttpPost]
public async Task<JsonResult> AjaxPostCall([FromBody] ClientSelectionFiltersViewModel filters)
{
//some code here....
return Json(result);
}
don't specify the "contentType": "application/json",
use different syntax of my json data with or without " "
...
Can you please tell me how to fix it?
Thanks I a lot.

Answer 1

You won't likely need [FromBody] on your action; try changing your JSON.stringify to:
"data": JSON.stringify({
"ContractTypes": $("#contractFilter").val(),
"PaymentChoices": $("#paymentFilter").val(),
"PopulationTypes": $("#populationFilter").val(),
"StrictFilteringContractTypes": $("#StrictFilteringContractTypes").is(":checked")
}),

Answer 2

This solution worked for me :
[HttpPost]
public async Task<JsonResult> AjaxPostCall(ClientSelectionFiltersViewModel filters, DataTableRequestParameters parameters)
{
//somecode...
}
And in JQuery :
var filters = {
ContractTypes: $("#contractFilter").val().join(', '),
PaymentChoices: $("#paymentFilter").val().join(', '),
PopulationTypes: $("#populationFilter").val().join(', '),
StrictFilteringContractTypes: $("#StrictFilteringContractTypes").is(":checked")
}
$("#tableServerSide").DataTable({
"processing": true,
"serverSide": true,
"filter": true,
"ajax": {
//"url": "/clientselection/ajaxpostcall", //doesn't work!!!
"url": "#Url.Action("AjaxPostCall", "ClientSelection")", //ok because of tag helper
"type": "POST",
"data": filters,
......
Thanks for your help!!

Answer 3

Remove "contentType"
Set "data" : jsonObject; without JSON.Stringy();
Remove [FromBody] from controller action method