登录Asp Net失败

Question

我想在asp中实现登录。净。我可以注册，AddPassword也是如此。我的密码已存储到我的数据库中。但是当我想再次登录时，它失败了。使用CheckPasswordAsync时，我遇到了异常。这是我的注册代码

var result = await UserManager.CreateAsync(user);
var isAddedPassword = await UserManager.AddPasswordAsync(user.Id, model.Password);

这是我想登录的时候

    [HttpPost]
    [AllowAnonymous]
    [ValidateAntiForgeryToken]
    public async Task<ActionResult> Login(LoginViewModel model, string returnUrl)
    {
        if (!ModelState.IsValid)
        {
            return View(model);
        }
        var foundUser = await UserManager.FindByEmailAsync(model.Email);
        if (foundUser == null)
        {
            ViewBag.Message = "NotRegistered";
            return View();
        }
        var user = await UserManager.FindAsync(foundUser.UserName, model.Password);
        var password = await _userManager.CheckPasswordAsync(foundUser, model.Password);
        var result = await SignInManager.PasswordSignInAsync(foundUser.UserName, model.Password, model.RememberMe, shouldLockout: false);

任何想法SignInManager.PasswordSignInAsync都会返回失败并且CheckPassword出现异常？