wp wp8: background tasks

Using System.Diagnostics;
using System.Windows;
using Microsoft.Phone.Scheduler;
using Microsoft.Phone.Shell;
using System.IO.IsolatedStorage;
using System.IO;

namespace MScheduledTaskAgent {
public
    class ScheduledAgent : ScheduledTaskAgent
    {
        /// <remarks>
        /// ScheduledAgent constructor, initializes UnhandledException handler
        /// </remarks>
        static ScheduledAgent()
        {
            // Subscribe to managed exception handler
            Deployment.Current.Dispatcher.BeginInvoke(delegate
            {
                Application.Current.UnhandledException += UnhandledException;
            });
        }

        /// Code to execute when unhandled exception occurs
        private static void UnhandledException(object sender, ApplicationUnhandledExceptionEventArgs e)
        {
            if (Debugger.IsAttached)
            {
                // Unhandled exception occurs Exception; break into the debugger
                Debugger.Break();
            }
        }

        /// <summary>
        /// The agent that runs the scheduled task
        /// </summary>
        /// <param name="task">
        /// call task
        /// </param>
        /// <remarks>
        /// Call this method when a scheduled or resource intensive task is called
        /// </remarks>
        protected override void OnInvoke(ScheduledTask task)
        {
            try
            {
                ShellToast toast = new ShellToast();
                toast.Title = "title";
                toast. Content = "content";
                toast.Show();
               
            }
            catch {
           
            }

            NotifyComplete();
        }
    }
}

wp8BackgroundService project MainPage.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Navigation;
using Microsoft.Phone.Controls;
using Microsoft.Phone.Shell;
using wp8BackgroundService.Resources;
using Microsoft.Phone.Scheduler;

namespace wp8BackgroundService
{
    /// <summary>
    ///
    /// 1.在wmappmanifest.xml中配置
    /// <Tasks>
    ///  <DefaultTask Name="_default" NavigationPage="MainPage.xaml"/>
    ///  <ExtendedTask Name="BackgroundTask">
    ///    <BackgroundServiceAgent Specifier="ScheduledTaskAgent" Name="MTaskAgent" Source="MScheduledTaskAgent" Type="MScheduledTaskAgent.ScheduledAgent" />
    /// </ExtendedTask>
    ///</Tasks>
    /// 1.ScheduledTaskAgent is fixed
    /// 2.MTaskAgent should be consistent with SERVICE_NAME in the current class
    /// 3.MScheduledTaskAgent is the dll name
    /// 4.MScheduledTaskAgent. Execution class in ScheduledAgent dll
    ///
    /// 2. Add a new project under the solution and select Scheduled Task Agent
    /// 3. Right-click on the wp8 project as the startup project
    /// 4. The solution generates the solution to generate the dll file
    /// 5.wp8 project reference right click to add reference solution project check OK
    ///
    /// </summary>
    public partial class MainPage : PhoneApplicationPage
    {
        // constructor
        public MainPage()
        {
            InitializeComponent();
          
        }

        private void start(object sender, RoutedEventArgs arg)
        {
            startService();
        }

        private String SERVICE_NAME = "MTaskAgent";

        private void startService()
        {
            PeriodicTask periodTask = ScheduledActionService.Find(SERVICE_NAME) as PeriodicTask;

            if(periodTask != null)
            {
                ScheduledActionService.Remove(SERVICE_NAME);
            }

            periodTask = new PeriodicTask(SERVICE_NAME);

            periodTask.Description = "后台任务";
            try
            {
                ScheduledActionService.Add(periodTask);
                ScheduledActionService.LaunchForTest(SERVICE_NAME, TimeSpan.FromSeconds(3));
                System.Diagnostics.Debug.WriteLine("后台任务启动");
            }
            catch(Exception ex)
            {
                System.Diagnostics.Debug.WriteLine(ex.Message);
            }

           

        }
    }
}

wmappmanifest.xml

<Tasks>
      <DefaultTask Name="_default" NavigationPage="MainPage.xaml"/>
      <ExtendedTask Name="BackgroundTask">
        <BackgroundServiceAgent Specifier="ScheduledTaskAgent" Name="MTaskAgent" Source="MScheduledTaskAgent" Type="MScheduledTaskAgent.ScheduledAgent" />
      </ExtendedTask>
    </Tasks>



This will also be processed after the project exits