C# 尝试登录Windows Phone 8.1应用程序时，Facebook ID的值为空

我正在尝试将Facebook登录与我的应用程序集成。我已经成功登录，获得了个人资料名称，但没有个人资料图片。经过检查，我意识到这是由于facebookID中的空值造成的。如何解决这个问题

private void LoadUserInfo()
        {
            var UISyncContext = TaskScheduler.FromCurrentSynchronizationContext();
            FBSession fbSession = FBSession.Instance;
            var fb = new FacebookClient(fbSession.Token.AccessToken);

            fb.GetCompleted += (o, e) =>
            {
                if (e.Error != null)
                {
                    Task.Factory.StartNew(() =>
                    {
                        Debug.WriteLine(e.Error.Message);
                    }, new System.Threading.CancellationToken(), TaskCreationOptions.PreferFairness, UISyncContext);
                    return;
                }

                var result = (IDictionary<string, object>)e.GetResultData();

                Task.Factory.StartNew(() =>
                {
                    TextBlock user_Name = FindChildControl<TextBlock>(homeSection, "user_Name") as TextBlock;
                    Image user_Image = FindChildControl<Image>(homeSection, "user_Image") as Image;
                    Debug.WriteLine("ID: " + fbSession.Token.AccessToken);
                    var profilePictureUrl = string.Format("https://graph.facebook.com/{0}/picture?type={1}&access_token={2}", fbSession.Token.FacebookId, "square", fbSession.Token.AccessToken);
                    user_Image.Source = new BitmapImage(new Uri(profilePictureUrl));
                    user_Name.Text = String.Format("{0} {1}", (string)result["first_name"], (string)result["last_name"]);
                }, new System.Threading.CancellationToken(), TaskCreationOptions.PreferFairness, UISyncContext);
            };

            fb.GetTaskAsync("me");
        }

---

我做错了什么？如何修复此问题？

我知道Facebook没有官方的Windows SDK，因此最好是在其中包含您正在使用的SDK的名称，并尝试对其进行标记，以便具有此专业知识的人员可以帮助您。

private void LoadUserInfo()
        {
            var UISyncContext = TaskScheduler.FromCurrentSynchronizationContext();
            FBSession fbSession = FBSession.Instance;
            var fb = new FacebookClient(fbSession.Token.AccessToken);

            fb.GetCompleted += (o, e) =>
            {
                if (e.Error != null)
                {
                    Task.Factory.StartNew(() =>
                    {
                        Debug.WriteLine(e.Error.Message);
                    }, new System.Threading.CancellationToken(), TaskCreationOptions.PreferFairness, UISyncContext);
                    return;
                }

                var result = (IDictionary<string, object>)e.GetResultData();

                Task.Factory.StartNew(() =>
                {
                    TextBlock user_Name = FindChildControl<TextBlock>(homeSection, "user_Name") as TextBlock;
                    Image user_Image = FindChildControl<Image>(homeSection, "user_Image") as Image;
                    Debug.WriteLine("ID: " + fbSession.Token.AccessToken);
                    var profilePictureUrl = string.Format("https://graph.facebook.com/{0}/picture?type={1}&access_token={2}", fbSession.Token.FacebookId, "square", fbSession.Token.AccessToken);
                    user_Image.Source = new BitmapImage(new Uri(profilePictureUrl));
                    user_Name.Text = String.Format("{0} {1}", (string)result["first_name"], (string)result["last_name"]);
                }, new System.Threading.CancellationToken(), TaskCreationOptions.PreferFairness, UISyncContext);
            };

            fb.GetTaskAsync("me");
        }