problems with column ordering in JQuery DataTable

I'm new to JQuery so please be patient.

I'm making a select that includes 5 options, including one to return all records.

<select id="sBusqueda" class="form-control fondo" name="sBusqueda" onchange="ModicaCampoTexto($(this));">
<option value="all">Todos</option>
<option value="nomProv">Nombre Proveedor</option>
<option value="nSolicitud">Nº Solicitud</option>
</select>

At the moment everything works fine and if I select the "all" option within my view, it reloads the records correctly, but... in ascending order and what I need is that it returns the data from highest to lowest.

Do you know what I'm doing wrong?

Here is my code:

$(document).ready(function () {
var tablaSolicitud = $('#TablaSolicitudes').DataTable({
"order": [[0, 'desc']],
"processing": true, // for show progress bar
"serverSide": true, // for process server side
"searching": false,
//"ordering": false,
"language": {
"url": "//cdn.datatables.net/plug-ins/1.10.16/i18n/Spanish.json"
},
"ajax": {
"url": '@Url.Action("CargaSolicitudes", "DPSolicitudes")',
"type": "POST",
"datatype": "json"
},
"columnDefs": [{
"targets": [0],
"visible": false,
"searchable": false
}],
"columns": [
{ "data": "DPSolicitudId", "name": "DPSolicitudId", "autoWidth": true },
{ "data": "NumeroSolicitud", "name": "NumeroSolicitud", "autoWidth": true },
{ "data": "CentroCosto", "name": "CentroCosto", "autoWidth": true },             
],
"lengthMenu": [[5 ,10, 15, 20, 25, 50, 100, 99999], [5, 10, 15, 20, 25, 50, 100, 'TODOS']],
});
$('#sBusqueda').change(function () {
var opcionSeleccionada = $(this).val();
// Verificar si la opción seleccionada es "Todos"
if (opcionSeleccionada === 'all') {
// Esto funciona 
// Here I need your help
var tablaReload = $('#TablaSolicitudes').DataTable();
tablaReload.order([[0, 'desc']]).draw();
}
});

I did not put the complete code because it would be very long, but the only thing I need is to know why it doesn't order the records from highest to lowest, thank you very much!

Your DataTable is using "serverSide": true. This means that all paging, filtering, and sorting is delegated to your server. DataTables does not perform any of that logic for you.

Specifically, when you choose your Todos option, that causes the following line of code to be executed:

tablaReload.order([[0, 'desc']]).draw();

But that does not mean DataTables performs any sorting.

Instead...

1. The order([[0, 'desc']]) sets the new sort order for the table.

2. The draw() automatically triggers a request to be sent to your server, using the DataTable's ajax option.

3. That request contains the new sort order. It's in the POST request body.

A fragment of that request body may look like this:

{
"order": [
{
"column": 0,
"dir": "desc"
}
]
}

You can see the order([[0, 'desc']]) has been added to the Ajax request's JSON.

It's up to your C# code to parse the request body, and then use this sorting instruction (along with the other request fields) to provide the new page of results - in the requested sort order.

You haven't shown us any of your C# code. But that is where you need to look.