Program Terminates when Background Event Fire

Question

I have made a Background Taks demo. It is a 95% % copy of the SOLUTION in this Question: Windows Phone 8.1 Background Task - Can't Debug and won't fire

The complete example OF THE SOLUTION can be download here : http://1drv.ms/1qCPLMY

The problem is when my event fires the program terminates. "my" solution can be downloaded here: http://1drv.ms/1x3z7Mp

So here is "my" code :

First the class implementing IBackgroundTask

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Windows.ApplicationModel.Background;
using Windows.Data.Xml.Dom;
using Windows.UI.Notifications;

namespace Tasks
{
    public sealed class Upload : IBackgroundTask
    {
        public void Run(IBackgroundTaskInstance taskInstance)
        {
            Debug.WriteLine("Hello IBackgroundTask");
            //return;
            var toastXml = ToastNotificationManager.GetTemplateContent(ToastTemplateType.ToastText02);
            var textElements = toastXml.GetElementsByTagName("text");

            var networkStateChangeEventDetails = (taskInstance.TriggerDetails as Windows.Networking.Connectivity.NetworkStateChangeEventDetails);
            if (networkStateChangeEventDetails == null)
                return;

            textElements[0].AppendChild(toastXml.CreateTextNode("I'm message from your task!"));
            ToastNotificationManager.CreateToastNotifier().Show(new ToastNotification(toastXml));
        }
    }
}

And here is the code for registering the Background taks:

private async void Button_Click(object sender, RoutedEventArgs e)
{
    Debug.WriteLine("Registering task");
    var taskRegistered = false;
    var exampleTaskName = "UploadTask";

    foreach (var task in BackgroundTaskRegistration.AllTasks)
    {
        if (task.Value.Name == exampleTaskName)
        {
            //taskRegistered = true;
            task.Value.Unregister(true);
            //   break;
        }
    }


    await BackgroundExecutionManager.RequestAccessAsync();
    if (!taskRegistered)
    {
        Debug.WriteLine("Registering task inside");
        var builder = new BackgroundTaskBuilder();
        builder.Name = exampleTaskName;
        builder.TaskEntryPoint = "Tasks.Upload";
        builder.SetTrigger(new SystemTrigger(SystemTriggerType.NetworkStateChange, false));
        BackgroundTaskRegistration task = builder.Register();
        //task.Completed += new BackgroundTaskCompletedEventHandler(NetworkStateChangeTaskOnCompleted);
        //task.Trigger += new BackgroundTaskCompletedEventHandler(NetworkStateChangeTaskOnCompleted);

                        await new MessageDialog("Task registered!").ShowAsync();
    }
}

private void NetworkStateChangeTaskOnCompleted(BackgroundTaskRegistration sender, BackgroundTaskCompletedEventArgs args)
{
    var toastXml = ToastNotificationManager.GetTemplateContent(ToastTemplateType.ToastText02);
    var textElements = toastXml.GetElementsByTagName("text");

    textElements[0].AppendChild(toastXml.CreateTextNode("NetworkStateChangeTaskOnCompleted() =>"));
    textElements[0].AppendChild(toastXml.CreateTextNode("I'm message from your task!"));

    ToastNotificationManager.CreateToastNotifier().Show(new ToastNotification(toastXml));
}

I get no exception, and no error mesage. The program just terminates, when the event fires. Same on both Device and Emulator.

You still need to include the relevant code in your question. Make your question self-contained so if links break in the future your question will still make sense. — eddie_cat, Nov 04 '14 at 15:38
Funny thing. I post a question a 4 people hate it. and no one even looked at it — Jens Borrisholt, Nov 04 '14 at 16:37
Nothing funny about people not wanting to wade through an entire solution that you have shown zero effort to debug yourself or provide a minimal example of the problem. — eddie_cat, Nov 04 '14 at 16:39
So there you go @eddie_cat, perhaps you could then look at the problem — Jens Borrisholt, Nov 04 '14 at 16:43

score 2 · Accepted Answer · answered Nov 04 '14 at 21:57

I've checked your project there are couple of things you need to improve:

first and most important - your BackgroundTask must be a Windows Runtime Componenet not a Class library (as it is now) - open properties of the Background Task and change it. BackgroundTask must be a runtime component - that's why your program terminates.
you will also need to change the namespace to the project's (file's) name - in this case you will have Task.Upload (instead of Tasks.Upload). Remember also to change entry in Declarations in package.appxmanifest file.

As I've tried after this changes your app should work fine.

Program Terminates when Background Event Fire

1 Answers1