asp.net-mvc – MVC 5 Owin Facebook Auth导致空参考异常

[AllowAnonymous]
    public async Task<ActionResult> ExternalLoginCallBACk(String returnUrl)
    {
        var loginInfo = await AuthenticationManager.GetExternalLoginInfoAsync();

{"id":"xxx","name":"xxx","first_name":"xxx","last_name":"xxx","link":
"https:\/\/www.facebook.com\/profile.php?id=xxx","LOCATIOn":{"id":"xxx","name":"xxx"},"gender":"xxx","timezone":1,"locale":"en_GB","verified":true,"updated_time":"2013-10-23T10:42:23+0000"}

这可能是身份OWIN扩展代码中的错误。我无法重现这个问题，因为我的Facebook有效载荷总是返回一个用户名字段在json，这是从你的fb响应中丢失。我不太清楚为什么不在那里

身份owin扩展方法中的代码对于身份的名称声明没有空值检查，与用户名字段相同。我们在内部提交了一个错误。

为了解决这个问题，您可以尝试使用以下代码替换ExternalLoginCallBACk方法：

[AllowAnonymous]
    public async Task<ActionResult> ExternalLoginCallBACk(String returnUrl)
    {
        var result = await AuthenticationManager.AuthenticateAsync(DefaultAuthenticationTypes.ExternalCookiE);
        if (result == null || result.Identity == null)
        {
            return RedirectToAction("Login");
        }

        var idClaim = result.Identity.FindFirst(ClaimTypes.NamEIDentifier);
        if (idClaim == null)
        {
            return RedirectToAction("Login");
        }

        var login = new UserLoginInfo(idClaim.Issuer,idClaim.value);
        var name = result.Identity.Name == null ? "" : result.Identity.Name.replace(" ","");

        // Sign in the user with this external login provider if the user already has a login
        var user = await UseRMANager.FindAsync(login);
        if (user != null)
        {
            await SignInAsync(user,isPersistent: falsE);
            return RedirectToLocal(returnUrl);
        }
        else
        {
            // If the user does not have an account,then prompt the user to create an account
            ViewBag.ReturnUrl = returnUrl;
            ViewBag.LoginProvider = login.LoginProvider;
            return View("ExternalLoginConfirmation",new ExternalLoginConfirmationViewModel { UserName = name });
        }
    }

当没有用户名从Facebook /谷歌返回时，代码将默认用户名设置为空。