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

@Html.EJS().Button("btn").Content("Get Items").Render()
@Html.EJS().DropDownList("customers").Placeholder("Select a customer").PopupHeight("200px").DataSource(dataManger =>
            dataManger.Url("http://services.odata.org/V4/Northwind/Northwind.svc/").Adaptor("ODataV4Adaptor").CrossDomain(true)).Fields(new DropDownListFieldSettings
            {
                Text = "ContactName",
                Value = "CustomerID"
            }).Query((string)ViewBag.query).Render()
<script>
 function actionComplete (e) {
         // get total items count
         console.log("Total items count: " + e.result.length);
         var element = document.createElement('p');
         element.innerText = "Total items count: " + e.result.length;
         document.getElementById('event').append(element);
    }
    document.getElementById('btn').onclick = () => {
        var Obj = document.getElementById("customers").ej2_instances[0];
        // get items count using getItems method
        console.log("Total items count: " + Obj.getItems().length);
        let element = document.createElement('p');
        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();
        }
    }
}