C# Background.BackgroundTaskDeferral类代码示例

        //
        // The Run method is the entry point of a background task.
        //
        public void Run(IBackgroundTaskInstance taskInstance)
        {
            Windows.Storage.ApplicationDataContainer localSettings = Windows.Storage.ApplicationData.Current.LocalSettings;
            Debug.WriteLine("Background " + taskInstance.Task.Name + " Starting...");

            // For performing asynchronous operations in the background task
            BackgroundTaskDeferral asyncDeferral = taskInstance.GetDeferral();

           

            //
            // Query BackgroundWorkCost
            // Guidance: If BackgroundWorkCost is high, then perform only the minimum amount
            // of work in the background task and return immediately.
            //
            var cost = BackgroundWorkCost.CurrentBackgroundWorkCost;
            var settings = ApplicationData.Current.LocalSettings;
            settings.Values["BackgroundWorkCost"] = cost.ToString();

            //
            // Associate a cancellation handler with the background task.
            //
            taskInstance.Canceled += new BackgroundTaskCanceledEventHandler(OnCanceled);

            //
            // Get the deferral object from the task instance, and take a reference to the taskInstance;
            //
            _deferral = taskInstance.GetDeferral();
            _taskInstance = taskInstance;

            _periodicTimer = ThreadPoolTimer.CreatePeriodicTimer(new TimerElapsedHandler(PeriodicTimerCallback), TimeSpan.FromSeconds(1));

            asyncDeferral.Complete();
        }

        /// <remarks>
        /// If you start any asynchronous methods here, prevent the task
        /// from closing prematurely by using BackgroundTaskDeferral as
        /// described in http://aka.ms/backgroundtaskdeferral
        /// </remarks>
        public async void Run(IBackgroundTaskInstance taskInstance)
        {
            // This deferral should have an instance reference, if it doesn't... the GC will
            // come some day, see that this method is not active anymore and the local variable
            // should be removed. Which results in the application being closed.
            _deferral = taskInstance.GetDeferral();
            var restRouteHandler = new RestRouteHandler();

            restRouteHandler.RegisterController<AsyncControllerSample>();
            restRouteHandler.RegisterController<FromContentControllerSample>();
            restRouteHandler.RegisterController<PerCallControllerSample>();
            restRouteHandler.RegisterController<SimpleParameterControllerSample>();
            restRouteHandler.RegisterController<SingletonControllerSample>();
            restRouteHandler.RegisterController<ThrowExceptionControllerSample>();
            restRouteHandler.RegisterController<WithResponseContentControllerSample>();

            var configuration = new HttpServerConfiguration()
                .ListenOnPort(8800)
                .RegisterRoute("api", restRouteHandler)
                .RegisterRoute(new StaticFileRouteHandler(@"Restup.DemoStaticFiles\Web"))
                .EnableCors(); // allow cors requests on all origins
            //  .EnableCors(x => x.AddAllowedOrigin("http://specificserver:<listen-port>"));

            var httpServer = new HttpServer(configuration);
            _httpServer = httpServer;
            
            await httpServer.StartServerAsync();

            // Dont release deferral, otherwise app will stop
        }

        public async void Run(IBackgroundTaskInstance taskInstance)
        {
            serviceDeferral = taskInstance.GetDeferral();
            taskInstance.Canceled += OnTaskCanceled;

            var triggerDetails = taskInstance.TriggerDetails as AppServiceTriggerDetails;

            if (triggerDetails == null)
            {
                serviceDeferral.Complete();
                return;
            }

            try
            {
                voiceServiceConnection = VoiceCommandServiceConnection.FromAppServiceTriggerDetails(triggerDetails);
                voiceServiceConnection.VoiceCommandCompleted += OnVoiceCommandCompleted;

                var voiceCommand = await voiceServiceConnection.GetVoiceCommandAsync();

                //Find the command name witch should match the VCD
                if (voiceCommand.CommandName == "buildit_help")
                {
                    var props = voiceCommand.Properties;
                    await CortanaHelpList();
                }
                await Task.Delay(1000);
                await ShowProgressScreen();
            }
            catch
            {
                Debug.WriteLine("Unable to process voice command");
            }
            serviceDeferral.Complete();
        }

        public async void Run(IBackgroundTaskInstance taskInstance)
        {
            // Create the deferral by requesting it from the task instance
            serviceDeferral = taskInstance.GetDeferral();

            AppServiceTriggerDetails triggerDetails = taskInstance.TriggerDetails as AppServiceTriggerDetails;

            if (triggerDetails != null && triggerDetails.Name.Equals("IMCommandVoice"))
            {
                voiceServiceConnection = VoiceCommandServiceConnection.FromAppServiceTriggerDetails(triggerDetails);

                VoiceCommand voiceCommand = await voiceServiceConnection.GetVoiceCommandAsync();

                // Perform the appropriate command depending on the operation defined in VCD
                switch (voiceCommand.CommandName)
                {
                    case "oldback":
                        VoiceCommandUserMessage userMessage = new VoiceCommandUserMessage();
                        userMessage.DisplayMessage = "The current temperature is 23 degrees";
                        userMessage.SpokenMessage = "The current temperature is 23 degrees";

                        VoiceCommandResponse response = VoiceCommandResponse.CreateResponse(userMessage, null);
                        await voiceServiceConnection.ReportSuccessAsync(response);
                        break;

                    default:
                        break;
                }
            }

            // Once the asynchronous method(s) are done, close the deferral
            serviceDeferral.Complete();
        }

        public void Run(IBackgroundTaskInstance taskInstance)
        {
            try {
                var triggerDetail = (AppServiceTriggerDetails) taskInstance.TriggerDetails;
                _deferral = taskInstance.GetDeferral();

                Hub.Instance.ForegroundConnection = triggerDetail.AppServiceConnection;
                Hub.Instance.ForegroundTask = this;

                taskInstance.Canceled += (s, e) => Close();
                triggerDetail.AppServiceConnection.ServiceClosed += (s, e) => Close();
            }
            catch (System.Exception e)
            {
                if (Hub.Instance.IsAppInsightsEnabled)
                {
                    Hub.Instance.RTCStatsManager.TrackException(e);
                }
                if (_deferral != null)
                {
                    _deferral.Complete();
                }
                throw e;
            }
        }

        /// <summary>
        /// Hệ thống gọi đến hàm này khi association backgroundtask được bật
        /// </summary>
        /// <param name="taskInstance"> hệ thống tự tạo và truyền vào đây</param>
        public async void Run(IBackgroundTaskInstance taskInstance)
        {
            //System.Diagnostics.Debug.WriteLine("background run");
            taskInstance.Canceled += new BackgroundTaskCanceledEventHandler(BackgroundTaskCanceled);
            taskInstance.Task.Completed += new BackgroundTaskCompletedEventHandler(BackgroundTaskCompleted);
            _backgroundstarted.Set();//
            _deferral = taskInstance.GetDeferral();

            //Playlist = new BackgroundPlaylist();
            _smtc = initSMTC();


            this._foregroundState = this.initForegroundState();

            BackgroundMediaPlayer.Current.CurrentStateChanged += BackgroundMediaPlayer_CurrentStateChanged;
            //Playlist = await BackgroundPlaylist.LoadBackgroundPlaylist("playlist.xml");
            Playlist = new BackgroundPlaylist();
            Playlist.ListPathsource = await BackgroundPlaylist.LoadCurrentPlaylist(Constant.CurrentPlaylist);
            
            if (_foregroundState != eForegroundState.Suspended)
            {
                ValueSet message = new ValueSet();
                message.Add(Constant.BackgroundTaskStarted, "");
                BackgroundMediaPlayer.SendMessageToForeground(message);
            }  
            Playlist.TrackChanged += Playlist_TrackChanged;
            BackgroundMediaPlayer.MessageReceivedFromForeground += BackgroundMediaPlayer_MessageReceivedFromForeground;
            BackgroundMediaPlayer.Current.MediaEnded +=Current_MediaEnded;
            ApplicationSettingHelper.SaveSettingsValue(Constant.BackgroundTaskState, Constant.BackgroundTaskRunning);
            isbackgroundtaskrunning = true;
            _loopState = eLoopState.None;
        }

        public async void Run(IBackgroundTaskInstance taskInstance)
        {
            // Ensure our background task remains running
            taskDeferral = taskInstance.GetDeferral();

            // Mutex will be used to ensure only one thread at a time is talking to the shield / isolated storage
            mutex = new Mutex(false, mutexId);

            // Initialize ConnectTheDots Settings
            localSettings.ServicebusNamespace = "iotbuildlab-ns";
            localSettings.EventHubName = "ehdevices";
            localSettings.KeyName = "D1";
            localSettings.Key = "iQFNbyWTYRBwypMtPmpfJVz+NBgR32YHrQC0ZSvId20=";
            localSettings.DisplayName = GetHostName();
            localSettings.Organization = "IoT Build Lab";
            localSettings.Location = "USA";

            SaveSettings();

            // Initialize WeatherShield
            await shield.BeginAsync();

            // Create a timer-initiated ThreadPool task to read data from I2C
            i2cTimer = ThreadPoolTimer.CreatePeriodicTimer(PopulateWeatherData, TimeSpan.FromSeconds(i2cReadIntervalSeconds));

            // Start the server
            server = new HttpServer(port);
            var asyncAction = ThreadPool.RunAsync((w) => { server.StartServer(shield, weatherData); });

            // Task cancellation handler, release our deferral there 
            taskInstance.Canceled += OnCanceled;

            // Create a timer-initiated ThreadPool task to renew SAS token regularly
            SasTokenRenewTimer = ThreadPoolTimer.CreatePeriodicTimer(RenewSasToken, TimeSpan.FromMinutes(15));
        }

        public async void Run(IBackgroundTaskInstance taskInstance) {
            try {
                // Ensure our background task remains running
                taskDeferral = taskInstance.GetDeferral();

                // Initialize cloud connection
                azureConnector = new AzureConnector();
                await azureConnector.InitAsync();

                // Initialize WeatherShield
                await shield.BeginAsync();

                // Create a timer-initiated ThreadPool task to read data from I2C
                ThreadPoolTimer.CreatePeriodicTimer(async (source) => {
                    await readAndSendWeatherRecord();
                }, TimeSpan.FromSeconds(weatherShieldReadInterval));

                // Task cancellation handler, release our deferral there
                taskInstance.Canceled += OnCanceled;
            } catch(Exception ex) {
                await LogExceptionAsync(nameof(Run), ex);
                if(Debugger.IsAttached) {
                    Debugger.Break();
                }

                // If it goes to shit here, rethrow which will terminate the process - but at least we have it logged!
                throw;
            }
        }

        public async void Run( IBackgroundTaskInstance taskInstance )
        {
            Deferral = taskInstance.GetDeferral();

            XParameter[] Params = SavedChannels.Parameters( "channel" );

            if ( Params.Length == 0 )
            {
                Deferral.Complete();
                return;
            }

            // Associate a cancellation handler with the background task.
            taskInstance.Canceled += new BackgroundTaskCanceledEventHandler( OnCanceled );

            foreach ( XParameter Param in Params )
            {
                CurrentTask = new XParameter( DateTime.Now.ToFileTime() + "" );
                CurrentTask.SetValue( new XKey[] {
                    new XKey( "name", taskInstance.Task.Name )
                    , new XKey( "start", true )
                    , new XKey( "end", false )
                } );

                PushNotificationChannel channel = await PushNotificationChannelManager.CreatePushNotificationChannelForApplicationAsync();

                if ( channel.Uri != Param.GetValue( "uri" ) )
                {
                    await RenewChannel( Param.GetValue( "provider" ), Param.Id, Uri.EscapeDataString( channel.Uri ) );
                }

            }

            Deferral.Complete();
        }

        public async void Run(IBackgroundTaskInstance taskInstance)
        {
            // Ensure our background task remains running
            taskDeferral = taskInstance.GetDeferral();

            // Mutex will be used to ensure only one thread at a time is talking to the shield / isolated storage
            mutex = new Mutex(false, mutexId);
         
            // Initialize ConnectTheDots Settings
            localSettings.ServicebusNamespace = "windowactuator-ns";
            localSettings.EventHubName = "ehdevices";
            localSettings.KeyName = "D1";
            localSettings.Key = "1uMOwjURpgGX9l5JqnYeatBkIRoLzP7qH8YGFUeAIrU=";
            localSettings.DisplayName = GetHostName();
            localSettings.Organization = "Ulster University";
            localSettings.Location = "North Europe";

            SaveSettings();

            // Initialize WeatherShield
            await shield.BeginAsync();

            // Create a timer-initiated ThreadPool task to read data from I2C
            i2cTimer = ThreadPoolTimer.CreatePeriodicTimer(PopulateWeatherData, TimeSpan.FromSeconds(i2cReadIntervalSeconds));

            // Start the server
            server = new HttpServer(port);
            var asyncAction = ThreadPool.RunAsync((w) => { server.StartServer(shield, weatherData); });

            // Task cancellation handler, release our deferral there 
            taskInstance.Canceled += OnCanceled;

            // Create a timer-initiated ThreadPool task to renew SAS token regularly
            SasTokenRenewTimer = ThreadPoolTimer.CreatePeriodicTimer(RenewSasToken, TimeSpan.FromMinutes(15));
        }

 public void Run(IBackgroundTaskInstance taskInstance)
 {
     _deferral = taskInstance.GetDeferral();
     Init();
     temperatureTimer = ThreadPoolTimer.CreatePeriodicTimer(temperatureTimer_Tick, TimeSpan.FromMinutes(5));
     thermostatStatusTimer = ThreadPoolTimer.CreatePeriodicTimer(thermostatStatusTimer_Tick, TimeSpan.FromMilliseconds(500));
 }

 public void Run(IBackgroundTaskInstance taskInstance)
 {
     deferral = taskInstance.GetDeferral();
     InitGPIO();
     
     GetBusArrivalData();
 }

 /// <summary>
 /// Entry point for the background task.
 /// </summary>
 public async void Run(IBackgroundTaskInstance taskInstance)
 {
     var triggerDetails = taskInstance.TriggerDetails as AppServiceTriggerDetails;
     if (null != triggerDetails && triggerDetails.Name == "LightControllerVoiceCommandService")
     {
         _deferral = taskInstance.GetDeferral();
         taskInstance.Canceled += (s, e) => _deferral.Complete();
         if (true != await InitializeAsync(triggerDetails))
         {
             return;
         }
         // These command phrases are coded in the VoiceCommands.xml file.
         switch (_voiceCommand.CommandName)
         {
             case "changeLightsState": await ChangeLightStateAsync(); break;
             case "changeLightsColor": await SelectColorAsync(); break;
             case "changeLightStateByName": await ChangeSpecificLightStateAsync(); break;
             default: await _voiceServiceConnection.RequestAppLaunchAsync(
                 CreateCortanaResponse("Launching HueLightController")); break;
         }
         // keep alive for 1 second to ensure all HTTP requests sent.
         await Task.Delay(1000);
         _deferral.Complete();
     }
 }

        /// <summary> 
        /// Background task entry point.
        /// </summary> 
        /// <param name="taskInstance"></param>
        public void Run(IBackgroundTaskInstance taskInstance)
        {
            Accelerometer = Accelerometer.GetDefault();

            if (null != Accelerometer)
            {
                SampleCount = 0;

                // Select a report interval that is both suitable for the purposes of the app and supported by the sensor.
                uint minReportIntervalMsecs = Accelerometer.MinimumReportInterval;
                Accelerometer.ReportInterval = minReportIntervalMsecs > 16 ? minReportIntervalMsecs : 16;

                // Subscribe to accelerometer ReadingChanged events.
                Accelerometer.ReadingChanged += new TypedEventHandler<Accelerometer, AccelerometerReadingChangedEventArgs>(ReadingChanged);

                // Take a deferral that is released when the task is completed.
                Deferral = taskInstance.GetDeferral();

                // Get notified when the task is canceled.
                taskInstance.Canceled += new BackgroundTaskCanceledEventHandler(OnCanceled);

                // Store a setting so that the app knows that the task is running.
                ApplicationData.Current.LocalSettings.Values["IsBackgroundTaskActive"] = true;
            }
        }

        /// <summary>
        /// Performs the work of a background task. The system calls this method when the associated
        /// background task has been triggered.
        /// </summary>
        /// <param name="taskInstance">
        /// An interface to an instance of the background task. The system creates this instance when the
        /// task has been triggered to run.
        /// </param>
        public void Run(IBackgroundTaskInstance taskInstance)
        {
            Debug.WriteLine("Background Audio Task " + taskInstance.Task.Name + " starting");

            this.systemMediaTransportControl = SystemMediaTransportControls.GetForCurrentView();
            this.systemMediaTransportControl.IsEnabled = true;
            this.systemMediaTransportControl.IsPauseEnabled = true;
            this.systemMediaTransportControl.IsPlayEnabled = true;
            this.systemMediaTransportControl.IsNextEnabled = true;
            this.systemMediaTransportControl.IsPreviousEnabled = true;

            // Wire up system media control events
            this.systemMediaTransportControl.ButtonPressed += this.OnSystemMediaTransportControlButtonPressed;
            this.systemMediaTransportControl.PropertyChanged += this.OnSystemMediaTransportControlPropertyChanged;

            // Wire up background task events
            taskInstance.Canceled += this.OnTaskCanceled;
            taskInstance.Task.Completed += this.OnTaskcompleted;

            // Initialize message channel 
            BackgroundMediaPlayer.MessageReceivedFromForeground += this.OnMessageReceivedFromForeground;

            // Notify foreground that we have started playing
            BackgroundMediaPlayer.SendMessageToForeground(new ValueSet() { { "BackgroundTaskStarted", "" } });
            this.backgroundTaskStarted.Set();
            this.backgroundTaskRunning = true;

            this.deferral = taskInstance.GetDeferral();
        }