Get the total count of data when remote data bind with DropDownList in ASP.NET Core DropDownList control

<ejs-button id="btn" content="Get Items"></ejs-button>
<div class="control-wrapper">
    <div id="default" style='padding-top:75px;'>
        <ejs-dropdownlist id="customers" query="new ej.data.Query().from('Customers').select(['ContactName', 'CustomerID']).take(6)" placeholder="Select a customer" popupHeight="200px">
            <e-dropdownlist-fields text="ContactName" value="CustomerID"></e-dropdownlist-fields>
            <e-data-manager url="https://services.odata.org/V4/Northwind/Northwind.svc/" adaptor="ODataV4Adaptor" crossDomain="true"></e-data-manager>
        </ejs-dropdownlist>
    </div>
</div>
<p id='event'> </p>
<script>
    document.getElementById('btn').onclick = () => {
        var element = document.createElement('p');
        document.getElementById("event").innerHTML = "";
        var Obj = document.getElementById("customers").ej2_instances[0];
        element.innerText = "Total items count: " + Obj.getItems().length;
        document.getElementById('event').append(element);
    };
</script>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using WebApplication1.Models;

namespace WebApplication1.Controllers
{
    public class DropDownListController : Controller
    {
        public ActionResult totalcount()
        {
            return View();
        }
    }
}