I have .net core solution with controller return data in view I want to send url to this project as Api and return data in web form application

I am not good in .net core and Api technology

The controller code

using System.Collections.Generic;
using System.Net;
using System.Net.Http;
using System.Threading.Tasks;
using GrandstreamClient.Manager;
using GrandstreamClient.Models;
using Microsoft.AspNetCore.Mvc;
using Newtonsoft.Json;

namespace GrandstreamClient.Controllers
{
    public class CDRController : Controller
    {
        RestManager manager;

        public CDRController()
        {
            manager = new RestManager();
        }

        public async Task<IActionResult> Index()
        {
            using (HttpClientHandler httpClientHandler = new HttpClientHandler())
            {
                httpClientHandler.ServerCertificateCustomValidationCallback = (message, cert, chain, errors) => { return true; };

                var credential = new NetworkCredential("username", "password");
                httpClientHandler.Credentials = credential;
                httpClientHandler.PreAuthenticate = true;

                using (HttpClient client = manager.Client(httpClientHandler))
                {
                    //HttpResponseMessage response = await client.GetAsync("todos/1");
                    HttpResponseMessage response = await client.GetAsync("cdrapi?format=json");

                    RootObject list = new RootObject();
                    List<CDR> ResultList = new List<CDR>();

                    if (response.IsSuccessStatusCode)
                    {

                        string result = await response.Content.ReadAsStringAsync();
                        //list = JsonConvert.DeserializeObject<ObjTest>(result);

                        list = JsonConvert.DeserializeObject<RootObject>(result);
                        foreach (var item in list.cdr_root)
                        {
                            if (!string.IsNullOrEmpty(item.recordfiles))
                            {
                                item.recordfiles = $"{client.BaseAddress}recapi?filename={item.recordfiles}";


                            }

                            if (item.main_cdr != null)
                            {
                                item.main_cdr.recordfiles = string.IsNullOrEmpty(item.main_cdr.recordfiles) ? string.Empty : $"{client.BaseAddress}recapi?filename={item.main_cdr.recordfiles}";

                            }

                            if (item.sub_cdr_1 != null)
                            {
                                item.sub_cdr_1.recordfiles = string.IsNullOrEmpty(item.sub_cdr_1.recordfiles) ? string.Empty : $"{client.BaseAddress}recapi?filename={item.sub_cdr_1.recordfiles}";
                            }

                            if (item.sub_cdr_2 != null)
                            {
                                item.sub_cdr_2.recordfiles = string.IsNullOrEmpty(item.sub_cdr_2.recordfiles) ? string.Empty : $"{client.BaseAddress}recapi?filename={item.sub_cdr_2.recordfiles}";

                            }

                            if (item.sub_cdr_3 != null)
                            {
                                item.sub_cdr_3.recordfiles = string.IsNullOrEmpty(item.sub_cdr_3.recordfiles) ? string.Empty : $"{client.BaseAddress}recapi?filename={item.sub_cdr_3.recordfiles}";
                            }

                            if (item.sub_cdr_4 != null)
                            {
                                item.sub_cdr_4.recordfiles = string.IsNullOrEmpty(item.sub_cdr_4.recordfiles) ? string.Empty : $"{client.BaseAddress}recapi?filename={item.sub_cdr_4.recordfiles}";

                            }

                            ResultList.Add(item);
                            //return Redirect(item.recordfiles);
                        }
                    }

                    return View(ResultList);

                }
            }

        }

    }
}

startup.cs 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;

namespace GrandstreamClient
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.Configure<CookiePolicyOptions>(options =>
            {
                // This lambda determines whether user consent for non-essential cookies is needed for a given request.
                options.CheckConsentNeeded = context => true;
                options.MinimumSameSitePolicy = SameSiteMode.None;
            });


            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Home/Error");
            }

            app.UseStaticFiles();
            app.UseCookiePolicy();

            app.UseMvc(routes =>
            {
                routes.MapRoute(
                    name: "default",
                    template: "{controller=CDR}/{action=Index}/{id?}");
            });
        }
    }
}

can any one help me to solve this