我不能在xamarin.android中调用FacebookCallback <loginresult>？

Question

将回调添加到您的活动中：

public class LoginActivity : Activity
    {
        ICallbackManager callbackManager;
        LoginButton loginButton;
        protected override void OnCreate (Bundle savedInstanceState)
        {

            base.OnCreate (savedInstanceState);
            FacebookSdk.SdkInitialize (Application.Context);
            // Create your application here
            SetContentView(Resource.Layout.LoginLayout);


            callbackManager = CallbackManagerFactory.Create ();

            LoginButton = FindViewById<LoginButton> (Resource.Id.btnloginbyfacebook);
            loginButton.RegisterCallback (callbackManager, new FacebookCallback<LoginResult> ()
                {
                    public void onSuccess(LoginResult loginResult) {
                        // App code
                    }
                    public void onCancel() {
                        // App code
                    }
                    public void onError(FacebookException exception) {
                        // App code   
                    }
                }
            );
            LoginButton.SetReadPermissions ();
        }




    }
}

无法在xamarin.android中调用新的IFacebookCallback（）？

文件是：https://developers.facebook.com/docs/facebook-login/android