public async Task<ActionResult> ChangePassword(ChangePasswordViewModel model)
 {
     if (!ModelState.IsValid)
     {
         return View(model);
     }
     var result = await _userManager.ChangePasswordAsync(User.Identity.GetUserId(), model.OldPassword, model.NewPassword);
     if (result.Succeeded)
     {
         var user = await _userManager.FindByIdAsync(User.Identity.GetUserId());
         if (user != null)
         {
             await _signInManager.SignInAsync(user, isPersistent: false, rememberBrowser: false);
         }
         return RedirectToAction("Index", new { Message = ManageMessageId.ChangePasswordSuccess });
     }
     AddErrors(result);
     return View(model);
 }
        public async Task<IHttpActionResult> ChangePassword(ChangePasswordViewModel model)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            IdentityResult result = await _userManager.ChangePasswordAsync(User.Identity.GetUserId(), model.OldPassword,
                model.NewPassword);

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

            return Ok();
        }