//
        // GET: ToDoList
        public async Task <ActionResult> Index()
        {
            string            userObjId  = System.Security.Claims.ClaimsPrincipal.Current.FindFirst("http://schemas.microsoft.com/identity/claims/objectidentifier").Value;
            SessionTokenCache tokenCache = new SessionTokenCache(userObjId, HttpContext);

            string accessToken = await SampleAuthProvider.Instance.GetUserAccessTokenAsync();

            await ExcelApiHelper.LoadWorkbook(accessToken);

            return(View(await ExcelApiHelper.GetToDoItems(accessToken)));
        }
        //
        // GET: ToDoList
        public async Task <ActionResult> Index()
        {
            string            userObjId  = System.Security.Claims.ClaimsPrincipal.Current.FindFirst("http://schemas.microsoft.com/identity/claims/objectidentifier").Value;
            SessionTokenCache tokenCache = new SessionTokenCache(userObjId, HttpContext);

            string     tenantId    = System.Security.Claims.ClaimsPrincipal.Current.FindFirst("http://schemas.microsoft.com/identity/claims/tenantid").Value;
            string     authority   = string.Format(ConfigurationManager.AppSettings["ida:AADInstance"], tenantId, "");
            AuthHelper authHelper  = new AuthHelper(authority, ConfigurationManager.AppSettings["ida:AppId"], ConfigurationManager.AppSettings["ida:AppSecret"], tokenCache);
            string     accessToken = await authHelper.GetUserAccessToken(Url.Action("Index", "Home", null, Request.Url.Scheme));

            await ExcelApiHelper.LoadWorkbook(accessToken);

            return(View(await ExcelApiHelper.GetToDoItems(accessToken)));
        }