显然，您可以通过向Startup.Auth.cs中的FacebookAuthenticationOptions对象添加范围来通过Facebook提供者执行此操作：
List<string> scope = new List<string>() { "email" };
var x = new FacebookAuthenticationOptions();
x.Scope.Add("email");
...
app.UseFacebookAuthentication(x);
如何与Google提供商一样？ GoogleAuthenticationOptions类/对象没有x.Scope属性！
解决方法
请在本帖子的底部看到更新！
以下适用于我的Facebook：
StartupAuth.cs：
var facebookAuthenticationOptions = new FacebookAuthenticationOptions()
{
AppId = "x",AppSecret = "y"
};
facebookAuthenticationOptions.Scope.Add("email");
app.UseFacebookAuthentication(facebookAuthenticationOptions);
ExternalLoginCallback方法：
var externalIdentity = HttpContext.GetOwinContext().Authentication.GetExternalIdentityAsync(DefaultAuthenticationTypes.ExternalCookie); var emailClaim = externalIdentity.Result.Claims.FirstOrDefault(c => c.Type == ClaimTypes.Email); var email = emailClaim.Value;
而对于Google：
StartupAuth.cs
app.UseGoogleAuthentication();
ExternalLoginCallback方法(与Facebook相同)：
var externalIdentity = HttpContext.GetOwinContext().Authentication.GetExternalIdentityAsync(DefaultAuthenticationTypes.ExternalCookie); var emailClaim = externalIdentity.Result.Claims.FirstOrDefault(c => c.Type == ClaimTypes.Email); var email = emailClaim.Value;
如果我在这里设置一个断点：
var email = emailClaim.Value;
我在调试器中看到Facebook和Google的电子邮件地址。
更新1：旧的答案让我困惑，所以我更新了我在我自己的项目中的代码，我刚刚调试，我知道工作。
更新2：使用新的ASP.NET Identity 2.0 RTM版本，您不再需要此帖中的任何代码。获取电子邮件的正确方法是简单地执行以下操作：
> Startup.Auth.cs
app.UseFacebookAuthentication(
appId: "x",appSecret: "y");
app.UseGoogleAuthentication();
> AccountController.cs
//
// GET: /Account/ExternalLoginCallback
[AllowAnonymous]
public async Task<ActionResult> ExternalLoginCallback(string returnUrl)
{
var loginInfo = await AuthenticationManager.GetExternalLoginInfoAsync();
if (loginInfo == null)
{
return RedirectToAction("Login");
}
// Sign in the user with this external login provider if the user already has a login
var result = await SignInHelper.ExternalSignIn(loginInfo,isPersistent: false);
switch (result)
{
case SignInStatus.Success:
return RedirectToLocal(returnUrl);
case SignInStatus.LockedOut:
return View("Lockout");
case SignInStatus.RequiresTwoFactorAuthentication:
return RedirectToAction("SendCode",new { ReturnUrl = returnUrl });
case SignInStatus.Failure:
default:
// If the user does not have an account,then prompt the user to create an account
ViewBag.ReturnUrl = returnUrl;
ViewBag.LoginProvider = loginInfo.Login.LoginProvider;
return View("ExternalLoginConfirmation",new ExternalLoginConfirmationviewmodel { Email = loginInfo.Email });
}
}
