在官方的 Mobile Service 身分驗證教學中，有提到在OnNavigatedTo()裡面就可以進行驗證，

官方範例的todo items也是這麼做，驗證過之後再去跟Azure Mobile Service撈資料。

官方文件在：http://azure.microsoft.com/zh-tw/documentation/articles/mobile-services-windows-phone-get-started-users/

 

這樣子的作法在之前Windows Phone 8.0以前是可以這麼做的

但到了Universal App則會出現問題
主要是因為Windows Phone 8.1在OnNavigatedTo()地同時若運作Azure Mobile Service驗證，則會又換一頁
這樣會有UI執行續的問題

 

造成Azure Mobile Service吐一個看似不像UI問題的錯誤：

An exception of type 'System.Exception' occurred in mscorlib.ni.dll but was not handled in user code

Additional information: The remote procedure call failed. (Exception from HRESULT: 0x800706BE)

 

解決這個問題讓Universal App Todoitem能夠順利運作必須要變動以下兩處

1.在App.xaml.cs裡面加入

        protected override void OnActivated(IActivatedEventArgs args)
        {
            base.OnActivated(args);

#if WINDOWS_PHONE_APP
            if (args.Kind == ActivationKind.WebAuthenticationBrokerContinuation)
            {
                App.MobileService.LoginComplete(args as WebAuthenticationBrokerContinuationEventArgs);
            }
#endif
        }

 

複寫OnActivated，讓App啟動過程中Windows Phone檢查是否已經登入過。

 

2.原先寫在MainPage.cs裡面的內容，通通先註解移除吧！

        protected override async void OnNavigatedTo(NavigationEventArgs e)
        {

            ////FB AUTH
            //var user = await App.MobileService.LoginAsync(MobileServiceAuthenticationProvider.Facebook);

            ////SHOW USER ID
            //await (new MessageDialog(App.MobileService.CurrentUser.UserId)).ShowAsync();
            //if (App.MobileService.CurrentUser.UserId != null)
            //{
            //    //await InitLocalStoreAsync(); // offline sync
            //    await RefreshTodoItems();
            //}

        }

 

 

3.在開頭，讓頁面載入完之後開一個dispatcher讓他執行登入程序(auth)

        public MainPage()
        {
            this.InitializeComponent();

            Loaded += async (sender, args) =>
            {
                await Dispatcher.RunAsync(CoreDispatcherPriority.Normal, auth);
            };
        }

 

 

4.把登入程序另外寫成一個名為auth的副程式(名子隨便你)

        private async void auth()
        {

            //FB AUTH
            var user = await App.MobileService.LoginAsync(MobileServiceAuthenticationProvider.Facebook);

            //SHOW USER ID
            await (new MessageDialog(App.MobileService.CurrentUser.UserId)).ShowAsync();
            if (App.MobileService.CurrentUser.UserId != null)
            {
                //await InitLocalStoreAsync(); // offline sync
                await RefreshTodoItems();
            }

        }

 

 

就大功告成啦！

 

 

thx for:

https://social.msdn.microsoft.com/Forums/vstudio/en-US/95c6569e-2fa2-43c8-af71-939e006a9b27/mobile-services-loginasync-remote-procedure-call-failed-hresult-0x800706be?forum=azuremobile