C＃Windows 8.1後臺在設備屏幕鎖定時運行的任務

Question

過去一週，我在爲Windows通用項目創建後臺任務方面做了大量工作。我有一個很難，並開始相信，當設備屏幕被鎖定時，不可能觸發後臺任務運行。我正在使用SystemTriggerType.Useraway來觸發後臺任務。我會發布迄今爲止我所擁有的。任何幫助，這將是真棒！

這裏是如何，我註冊的後臺任務

public static void RegisterTask() 
    { 
     try 
     { 
      var taskRegistered = false; 
      var builder = new BackgroundTaskBuilder(); 

      foreach (var task in BackgroundTaskRegistration.AllTasks) 
      { 
       if (task.Value.Name == "ResponderBackgroundTask") 
       { 
        Debug.WriteLine(task.Value.Name + " Task Already Registered!!"); 
        taskRegistered = true; 
        break; 
       } 
      } 

      if (!taskRegistered) 
      { 
       builder.Name = "ResponderBackgroundTask"; 
       builder.TaskEntryPoint = "BackgroundGps.BackgroundTask"; 
       builder.AddCondition(new SystemCondition(SystemConditionType.UserNotPresent)); 
       builder.AddCondition(new SystemCondition(SystemConditionType.InternetAvailable)); 
       builder.SetTrigger(new SystemTrigger(SystemTriggerType.UserAway, false)); 
       builder.CancelOnConditionLoss = true; 
       var register = builder.Register(); 

       register.Completed += new BackgroundTaskCompletedEventHandler(OnComplete); 
      } 
     } 
     catch (Exception ex) 
     { 
      Debug.WriteLine(ex.ToString()); 
      throw; 
     } 
    } 

這裏是backgroundtask：

async public void Run(IBackgroundTaskInstance taskInstance) 
{ 
    taskInstance.Canceled += new BackgroundTaskCanceledEventHandler(OnCanceled); 

    Debug.WriteLine("Inside Run......."); 

    BackgroundTaskDeferral deferral = taskInstance.GetDeferral(); 

    await Geolocate(); 

    deferral.Complete(); 
} 

async static Task<HttpResponseMessage> Geolocate() 
{ 
    Debug.WriteLine("Inside Async Geolocate"); 

    HttpResponseMessage response = new HttpResponseMessage(); 

    Geolocator geolocator = new Geolocator(); 
    geolocator.DesiredAccuracy = (PositionAccuracy) 20; 
    geolocator.DesiredAccuracyInMeters = 30; 

    var networkStatus = NetworkInformation.GetInternetConnectionProfile(); 
    bool status = true; 

    while (status) 
    { 
     networkStatus = NetworkInformation.GetInternetConnectionProfile(); 

     Geoposition position = await geolocator.GetGeopositionAsync().AsTask(); 

     var latitude = position.Coordinate.Point.Position.Latitude; 
     var longitude = position.Coordinate.Point.Position.Longitude; 

     HttpClient client = new HttpClient(); 
     response = await client.GetAsync("http://www.mylocation.com/location?=latitude&longitude"); 
     Debug.WriteLine(response); 

     if (networkStatus == null) 
     { 
      status = false; 
     } 

     if (cancelRequest == true) 
     { 
      return response; 
     } 

     await Task.Delay(15000); 
    } 

    return response; 
} 

Answer 1

我在UWP項目的一些問題與後臺任務時，我已經使用了推送通知。

UWPBackgroundTasks的主要問題在於，它們假設非常輕並且消耗的CPU時間不是很多，否則操作系統會關閉它。

我的問題是，我試圖通過使用非常繁重的服務訪問本地數據庫，這花費了CPU時間並且被操作系統關閉。我的日誌在一行中間被切斷，導致我的日誌記錄器不能足夠快地寫入消息。

嘗試在你的BackgroundTask中放置一些日誌，看看他是否被觸發器提升，並尋找可能導致它被取消的沉重操作。

Web請求也可能是問題...