public IActionResult Get()
        {
            UpdateUserNameViewModel model = new UpdateUserNameViewModel();
            var userId     = _caller.Claims.Single(c => c.Type == "id");
            var OnlineUser = _userManager.FindByIdAsync(userId.Value).Result;

            model.UserName = OnlineUser.UserName;
            model.Id       = OnlineUser.Id;

            return(new OkObjectResult(model));
        }
        public IActionResult Put(string id, [FromBody] UpdateUserNameViewModel model)
        {
            if (model == null)
            {
                return(null);
            }

            var admin = _userManager.FindByIdAsync(id).Result;

            if (admin == null)
            {
                return(NotFound());
            }

            admin.UserName = model.UserName;
            var result = _userManager.UpdateAsync(admin).Result;

            if (!result.Succeeded)
            {
                return(BadRequest());
            }

            return(Ok());
        }