Windows Phone 8.1应用中的后台任务在一天中的特定时间触发

Question

Im developing a windows phone 8.1 WinRT c#/Xaml app that needs to download some json string on every morning.

How do I get my background task to run on that specific time of the day. What trigger should I use for it ?

Please someone guide me or point me to some tutorial.

Thank you

Answer 1

This is how I solved my problem.

public async static Task RegisterBackgroundAgentAsync(string time)
    {
        var Datetime = DateTime.ParseExact(time, "HHmm", new System.Globalization.CultureInfo("en-US"));
        var taskname = "BackgroundAgentTask";
        var builder = new BackgroundTaskBuilder();
        builder.Name = taskname;
        builder.TaskEntryPoint = "BackgroundAgent.BackgroundAgentTask";
        TimeSpan ts = Datetime - DateTime.ParseExact(DateTime.Now.Hour.ToString("00") + DateTime.Now.Minute.ToString("00"), "HHmm", new CultureInfo("en-US"));
        if (ts.TotalMinutes < 15)
        {
           if (ts.TotalMinutes < 0)
           {
               if (1440 + ts.TotalMinutes > 15)
                  builder.SetTrigger(new TimeTrigger((uint)(1440 + ts.TotalMinutes), false));
               else
                  builder.SetTrigger(new TimeTrigger(15, false));
           }
           else
           {
               if (ts.TotalMinutes == 0)
                   builder.SetTrigger(new TimeTrigger(1440, false));
               else
                   builder.SetTrigger(new TimeTrigger(15, false));
           }
        }
        else
            builder.SetTrigger(new TimeTrigger((uint)ts.TotalMinutes, false));
        BackgroundTaskRegistration result;  
        var bas = (await BackgroundExecutionManager.RequestAccessAsync());
        if (bas == BackgroundAccessStatus.AllowedMayUseActiveRealTimeConnectivity)
            result = builder.Register();
    }