ScheduledTaskAgent not working for updating tiles in Windows Phone - c#

I am working on a Windows Phone 7 app and trying to implement the features of a Windows Phone 8 like wide tiles into it. I achieved it using reflection but when i wanted to update the tile using a ScheduledAgent for a Periodic Task the tile is not getting created.
The scheduled agent OnInvoke code looks like
protected override void OnInvoke(ScheduledTask task)
{
//TODO: Add code to perform your task in background
if (task is PeriodicTask)
{
//Update the tile using Scheduled Task
CreateTileForWindowsPhone.CreateWideTile();
}
NotifyComplete();
}
I created the tile using this code
public class CreateTileForWindowsPhone
{
private static Version TargetedVersion = new Version(7, 10, 8858);
public static bool IsTargetedVersion { get { return Environment.OSVersion.Version >= TargetedVersion; } }
public static void CreateWideTile()
{
if (IsTargetedVersion)
{
try
{
// Get the new FlipTileData type.
Type flipTileDataType = Type.GetType("Microsoft.Phone.Shell.FlipTileData, Microsoft.Phone");
// Get the ShellTile type so we can call the new version of "Update" that takes the new Tile templates.
Type shellTileType = Type.GetType("Microsoft.Phone.Shell.ShellTile, Microsoft.Phone");
// Loop through any existing Tiles that are pinned to Start.
QuotesCollection aq = new QuotesCollection();
Random rand = new Random();
int randNum = rand.Next(0, 163);
//String wideBackStr = "Dont be the same, Be Better.";
String wideBackStr = aq.quotes[randNum];
foreach (var tileToUpdate in ShellTile.ActiveTiles)
{
// Get the constructor for the new FlipTileData class and assign it to our variable to hold the Tile properties.
var UpdateTileData = flipTileDataType.GetConstructor(new Type[] { }).Invoke(null);
// Set the properties.
SetProperty(UpdateTileData, "WideBackgroundImage", new Uri("/images/QuottedWideTile.png", UriKind.Relative));
SetProperty(UpdateTileData, "WideBackContent", wideBackStr);
// Invoke the new version of ShellTile.Update.
shellTileType.GetMethod("Update").Invoke(tileToUpdate, new Object[] { UpdateTileData });
break;
}
}
catch
{
MessageBox.Show("Tile Error Caught");
}
}
}
private static void SetProperty(object instance, string name, object value)
{
var setMethod = instance.GetType().GetProperty(name).GetSetMethod();
setMethod.Invoke(instance, new object[] { value });
}
}
i made a register agent method to register the Periodic Task
private void RegisterAgent()
{
string taskName = "MyTask";
try
{
if (ScheduledActionService.Find(taskName) != null)
{
//if the agent exists, remove and then add it to ensure
//the agent's schedule is updated to avoid expiration
ScheduledActionService.Remove(taskName);
}
PeriodicTask periodicTask = new PeriodicTask(taskName);
periodicTask.Description = "Random Quote Update On Tile";
ScheduledActionService.Add(periodicTask);
}
catch (InvalidOperationException exception)
{
MessageBox.Show(exception.Message);
}
catch (SchedulerServiceException schedulerException)
{
MessageBox.Show(schedulerException.Message);
}
}
and called the register in the app launching
private void Application_Launching(object sender, LaunchingEventArgs e)
{
RegisterAgent();
}
But the wide tile is not being created when i run the app.
Wide tile creation used to work before i used scheduled agents to update the tile. I used to create a wide tile just by calling that function in application launching.
private void Application_Launching(object sender, LaunchingEventArgs e)
{
CreateTileForWindowsPhone.CreateWideTile();
}
WHy is the tile not being created. Am i doing something wrong?

Deployment.Current.Dispatcher.BeginInvoke(
CreateTileForWindowsPhone.CreateWideTile);

Related

Asynchronous operations within a loop - how to keep control of execution?

Follow-on question to this one.
I am trying to generate and save a series of images. Rendering is done by Helix Toolkit, which I am told utilises the WPF composite render thread. This is causing problems because it executes asynchronously.
My original problem was that I couldn't save a given image because it hadn't yet been rendered at that time I was trying to save it. The above answer provides a workaround to this by putting the 'save' operation inside an Action which is called with low priority, thus ensuring that the rendering completes first.
This is fine for one image, but in my application I require multiple images. As it stands I cannot keep control of the sequence of events because they occur asynchronously. I am using a For loop which just continues regardless of the progress of rendering and saving the images. I need the images to be generated one by one, with enough time for rendering and saving before starting the next one.
I have tried putting delays in the loop but that causes its own problems. For instance an async await as commented in the code causes cross-threading issues because the data was created on a different thread from where the rendering is being done. I tried putting in a simple delay but then that just locks everything up - I think in part because the save operation I am waiting on has very low priority.
I cannot simply treat it as a batch of separate unrelated asynchronous tasks because I am using a single HelixViewport3D control in the GUI. The images have to be generated sequentially.
I did try a recursive method where SaveHelixPlotAsBitmap() calls DrawStuff() but that wasn't working out very well, and it doesn't seem a good approach.
I tried setting a flag ('busy') on each loop and waiting for it to be reset before continuing but that wasn't working - again, because of the asynchronous execution. Similarly I tried using a counter to keep the loop in step with the number of images that had been generated but ran into similar problems.
I seem to be going down a rabbit hole of threading and asynchronous operations that I don't want to be in.
How can I resolve this?
class Foo {
public List<Point3D> points;
public Color PointColor;
public Foo(Color col) { // constructor creates three arbitrary 3D points
points = new List<Point3D>() { new Point3D(0, 0, 0), new Point3D(1, 0, 0), new Point3D(0, 0, 1) };
PointColor = col;
}
}
public partial class MainWindow : Window
{
int i = -1; // counter
public MainWindow()
{
InitializeComponent();
}
private void Go_Click(object sender, RoutedEventArgs e) // STARTING POINT
{
// Create list of objects each with three 3D points...
List<Foo> bar = new List<Foo>(){ new Foo(Colors.Red), new Foo(Colors.Green), new Foo(Colors.Blue) };
foreach (Foo b in bar)
{
i++;
DrawStuff(b, SaveHelixPlotAsBitmap); // plot to helixViewport3D control ('points' = list of 3D points)
// This is fine the first time but then it runs away with itself because the rendering and image grabbing
// are asynchronous. I need to keep it sequential i.e.
// Render image 1 -> save image 1
// Render image 2 -> save image 2
// Etc.
}
}
private void DrawStuff(Foo thisFoo, Action renderingCompleted)
{
//await System.Threading.Tasks.Task.Run(() =>
//{
Point3DCollection dataList = new Point3DCollection();
PointsVisual3D cloudPoints = new PointsVisual3D { Color = thisFoo.PointColor, Size = 5.0f };
foreach (Point3D p in thisFoo.points)
{
dataList.Add(p);
}
cloudPoints.Points = dataList;
// Add geometry to helixPlot. It renders asynchronously in the WPF composite render thread...
helixViewport3D.Children.Add(cloudPoints);
helixViewport3D.CameraController.ZoomExtents();
// Save image (low priority means rendering finishes first, which is critical)..
Dispatcher.BeginInvoke(renderingCompleted, DispatcherPriority.ContextIdle);
//});
}
private void SaveHelixPlotAsBitmap()
{
Viewport3DHelper.SaveBitmap(helixViewport3D.Viewport, $#"E:\test{i}.png", null, 4, BitmapExporter.OutputFormat.Png);
}
}
Note These examples are just to prove a concept, there is work needed on the TaskCompletionSource to handle errors
Given this test window
<Window x:Class="WpfApp2.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
Title="MainWindow" Height="450" Width="800">
<Grid>
<StackPanel x:Name="StackPanel"/>
</Grid>
</Window>
Here is an example of how to use events to know when the view is in the state that you want.
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
namespace WpfApp2
{
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
DoWorkAsync();
}
private async Task DoWorkAsync()
{
for (int i = 0; i < 10; i++)
{
await RenderAndCapture();
}
}
private async Task RenderAndCapture()
{
await RenderAsync();
CaptureScreen();
}
private Task RenderAsync()
{
var taskCompletionSource = new TaskCompletionSource<object>();
Dispatcher.Invoke(() =>
{
var panel = new TextBlock {Text = "NewBlock"};
panel.Loaded += OnPanelOnLoaded;
StackPanel.Children.Add(panel);
void OnPanelOnLoaded(object sender, RoutedEventArgs args)
{
panel.Loaded -= OnPanelOnLoaded;
taskCompletionSource.TrySetResult(null);
}
});
return taskCompletionSource.Task;
}
private void CaptureScreen()
{
// Capture Image
}
}
}
If you want to have your sync method called from outside you can implement a task queue.
using System;
using System.Threading;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
namespace WpfApp2
{
public class TaskQueue
{
private readonly SemaphoreSlim _semaphore;
public TaskQueue()
{
_semaphore = new SemaphoreSlim(1);
}
public async Task Enqueue(Func<Task> taskFactory)
{
await _semaphore.WaitAsync();
try
{
await taskFactory();
}
finally
{
_semaphore.Release();
}
}
}
public partial class MainWindow : Window
{
private readonly TaskQueue _taskQueue;
public MainWindow()
{
_taskQueue = new TaskQueue();
InitializeComponent();
DoWork();
}
private void DoWork()
{
for (int i = 0; i < 10; i++)
{
QueueRenderAndCapture();
}
}
private void QueueRenderAndCapture()
{
_taskQueue.Enqueue(() => RenderAndCapture());
}
private async Task RenderAndCapture()
{
await RenderAsync();
CaptureScreen();
}
private Task RenderAsync()
{
var taskCompletionSource = new TaskCompletionSource<object>();
Dispatcher.Invoke(() =>
{
var panel = new TextBlock {Text = "NewBlock"};
panel.Loaded += OnPanelOnLoaded;
StackPanel.Children.Add(panel);
void OnPanelOnLoaded(object sender, RoutedEventArgs args)
{
panel.Loaded -= OnPanelOnLoaded;
taskCompletionSource.TrySetResult(null);
}
});
return taskCompletionSource.Task;
}
private void CaptureScreen()
{
// Capture Screenshot
}
}
}
This will make sure the UI is in the state required for each iteration
You will of course need to expand this so that you listen to the Loaded event of each point that you wish to render.
Edit:
As PointsVisual3D does not have the Loaded event you can complete the task by hooking onto the event you had previously used. Not ideal, but it should work.
private Task RenderAsync()
{
var taskCompletionSource = new TaskCompletionSource<object>();
Dispatcher.Invoke(() =>
{
var panel = new TextBlock {Text = "NewBlock"};
StackPanel.Children.Add(panel);
Dispatcher.BeginInvoke(new Action(() =>
{
taskCompletionSource.TrySetResult(null);
}), DispatcherPriority.ContextIdle);
});
return taskCompletionSource.Task;
}
Solution below. This is my implementation of the code provided in Jason's answer. All credit to Jason for the important bits.
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
private void Go_Click(object sender, RoutedEventArgs e) // STARTING POINT
{
DoWorkAsync();
}
private async Task DoWorkAsync()
{
// Create list of objects each with three 3D points...
List<Foo> bar = new List<Foo>() { new Foo(Colors.Red), new Foo(Colors.Green), new Foo(Colors.Blue) };
int i = -1; // init counter
foreach (Foo b in bar)
{
i++;
await RenderAndCapture(b, i);
}
}
private async Task RenderAndCapture(Foo b, int i)
{
await RenderAsync(b);
SaveHelixPlotAsBitmap(i);
}
private Task RenderAsync(Foo b)
{
var taskCompletionSource = new TaskCompletionSource<object>();
Dispatcher.Invoke(() =>
{
DrawStuff(b);
Dispatcher.BeginInvoke(new Action(() =>
{
taskCompletionSource.TrySetResult(null);
}), DispatcherPriority.ContextIdle);
});
return taskCompletionSource.Task;
}
private void DrawStuff(Foo thisFoo)
{
Point3DCollection dataList = new Point3DCollection();
PointsVisual3D cloudPoints = new PointsVisual3D { Color = thisFoo.PointColor, Size = 5.0f };
foreach (Point3D p in thisFoo.points)
{
dataList.Add(p);
}
cloudPoints.Points = dataList;
// Add geometry to helixPlot. It renders asynchronously in the WPF composite render thread...
helixPlot.Children.Add(cloudPoints);
helixPlot.CameraController.ZoomExtents();
}
private void SaveHelixPlotAsBitmap(int i) // screenshot
{
Viewport3DHelper.SaveBitmap(helixPlot.Viewport, $#"E:\test{i}.png", null, 4, BitmapExporter.OutputFormat.Png);
}
}

windows service method not working

I am new in windows service c#. I have a class library called JobAdminLib which has a class call ArchiveAutomationAdministrator. This class has a method called CountJobs(). I have created a windows service which would run this particular method at the scheduled interval of time. But it does not seems to work for me. Log reports are saying its running but the function that the method is supposed to perform is not working.
I have attached code for reference
public class ArchiveAutomationAdministrator
{
JobRepository repository = new JobRepository();
public IEnumerable<LiveJobs> GetCurrentlyRetentionJobs(Func<LiveJobs, bool>
criteria = null)
{
return from job in repository.GetCurrentlyRetentionJobs() select job;
}
public void countJobs()
{
var count = from job in repository.GetCurrentlyRetentionJobs() select job;
int[] JobCount = new int[count.Count()];
for (int i = 1; i <= JobCount.Length; i++)
{
string jobnumber = repository.GetCurrentlyRetentionJobs().First().JobNumber;
JobAdministrator admin = new JobAdministrator(repository);
admin.ArchiveJob(jobnumber);
}
}
}
Following is my windows service
public partial class Scheduler : ServiceBase
{
private Timer timer1 = null;
public Scheduler()
{
InitializeComponent();
}
protected override void OnStart(string[] args)
{
timer1 = new Timer();
this.timer1.Interval = 5000;
this.timer1.Elapsed += new
System.Timers.ElapsedEventHandler(this.timer1_Tick);
timer1.Enabled = true;
Library.WriteErrorLog("test windows service started");
}
public void timer1_Tick(object sender, ElapsedEventArgs e)
{
this.task();
Library.WriteErrorLog("Job running successfully");
}
protected override void OnStop()
{
timer1.Enabled = false;
Library.WriteErrorLog("Service Stopped");
}
public void task()
{
Library.WriteErrorLog("Inside task");
ArchiveAutomationAdministrator admin = new ArchiveAutomationAdministrator();
admin.countJobs();
}
}
check if windows servers has the authority to run
if it Ok
go to windows service list
1- open run cmd
2- type services.msc
3- right click on your service name
4- in login tab click on Local System Account and Check Allow Service To Interact with desktop
That countJobs method has a crazy way of enumerating a list. Its hard to tell if this will work but try the below...
public void countJobs()
{
foreach (var job in repository.GetCurrentlyRetentionJobs())
{
Library.WriteErrorLog("Archiving job " + job.JobNumber);
string jobnumber = job.JobNumber;
JobAdministrator admin = new JobAdministrator(repository);
admin.ArchiveJob(jobnumber);
}
}
that way you will get logging inside the loop and you'll be able to tell if there is anything to actually process.

Correct Event handling in C#

this is basically a follow up to a previous question (Triggering an event in c# from c++ and declaring LPCWSTR). I've revised my code based on the answers and comments I have received and I solved the initial issue, which was passing the event to the GpioSetupInterruptPin from a gpio api. I don't have a lot of documentation on the api but what i'm trying to achieve is: have a form with a white label; after pressing a switch, the label turns yellow.
The problem i'm having now is the event seems to trigger as soon as it's created (the "execute" message is passed to the debug dialog and the label turns yellow) but it doesn't do anything when i toggle the switch. I was told in the last question to use WaitForSingleObject but i'm not really sure where to call it and this article only added to my confusion.
public partial class Form1 : Form
{
// P/Invoke CreateEvent and WaitForSingleObject
private void GPIO_Open() //get handle for gpio
private void GPIO_Output() //output pin declaration
private void button1_Click(object sender, EventArgs e)
{
Interrupt_Setup();
}
private void Interrupt_Setup()
{
hGPIO = GPIOapi.GpioOpenHandle(); //returns a handle to the gpio
GIPO_ON = true;
Debug.WriteLine("Driver open \n" + hGPIO);
GPIO_Output(); //set output pins
GPIO_Interrupt(Trigger); //configure interrupt
}
private void GPIO_Interrupt(string trigger)
{
bool ok;
_Main();
//INTERRUPT DECALRATION
ok = GPIOapi.GpioSetupInterruptPin(hGPIO, port6, 4, GPIOapi.INT_TRIGGER_MODE.TRIGGER_MODE_EDGE,
GPIOapi.INT_TRIGGER_POLARITY.TRIGGER_POL_HIGH_RISING, trigger, true);
Thread waitThread=new Thread(WaitForTrigger);
waitThread.Start();
if (!ok)
Debug.WriteLine("NO interrupt");
else
Debug.WriteLine("Interrupt set for:" + port6 + "04" + " at " + hGPIO);
}
public static string Trigger = "InputProcessUpdateHandler";
public static IntPtr handle = CreateEvent(IntPtr.Zero, false, false, Trigger); //used P/Invoke
private static InputProcessor inputProcessor = null;
public Color[] color =
{
Color.Orchid, Color.DarkOrchid, Color.GreenYellow, Color.CornflowerBlue, Color.SteelBlue,Color.Crimson
};
public int i = 0;
public void WaitForTrigger()
{
while(true)
{try
{
if (WaitForSingleObject(handle, 0xFFFFFFFF) == false)
{
BeginInvoke(((System.Action)(() =>label2.BackColor = color[i])));
i++;
if (i > 4)
i = 0;
}
Thread.Sleep(300);
}
catch (Exception e)
{ Debug.WriteLine("exception: " + e); }}
}
}
private void _Main()
{
inputProcessor = new InputProcessor();
ShowToggle showToggle = new ShowToggle(inputProcessor);
inputProcessor.Process(label1);
}
public class ShowToggle
{
private InputProcessor _inputProcessor = null;
public ShowToggle(InputProcessor inputProcessor)
{
_inputProcessor = inputProcessor;
_inputProcessor.updateHandledBy += InputProcessUpdateHandler;
}
private void InputProcessUpdateHandler(Label label)
{
label.BackColor = Color.Yellow;
Debug.Write("execute");
}
}
public class InputProcessor
{
public delegate void InputProcessUpdateHandler(Label label);
public event InputProcessUpdateHandler updateHandledBy = null;
public void Process(Label label)
{
if (updateHandledBy != null)
updateHandledBy(label);
}
}
If anyone could help me with this, I would be very grateful.
*** I got it working but it looks a right mess. Could anyone help me straighten it out?
You code is really confusing to me. I think what you want is something like this. Bear in mind I'm typing this into the SO text editor, so don't expect it to compile and just work - it's a guide. Consider it a step above pseudocode.
public class DeviceInterrupt
{
IntPtr m_gpio;
string m_eventName;
public event EventHandler OnInterrupt;
public DeviceInterrupt(int port)
{
// get a driver handle
m_gpio = GPIO_Open();
// generate some unique event name
m_eventName = "GPIO_evt_" + port;
// wire up the interrupt
GpioSetupInterruptPin(m_gpio, port, m_eventName, ...);
// start a listener
new Thread(EventListenerProc)
{
IsBackground = true,
Name = "gpio listener"
}
.Start();
}
public void Dispose()
{
// TODO: release the handle
}
private void EventListenerProc()
{
// create the event with the name we sent to the driver
var wh = new WaitHandle(false, m_eventName);
while (true)
{
// wait for it to get set by the driver
if (wh.WaitOne(1000))
{
// we have an interrupt
OnInterrupt.Fire(this, EventArgs.Empty);
}
}
}
}
Usage would then be something like this:
var intr = new DeviceInterrupt(4);
intr.OnInterrupt += MyHandler;
....
void MyHandler(object sender, EventArgs a)
{
Debug.WriteLine("Interrupt occurred!");
}
Note
The Compact Framework doesn't support actual named system events, so the named WaitHandle I use in my code above is not a CF-supplied WaitHandle. Instead I'm using the one from the Smart Device Framework. You could also P/Invoke to CreateEvent and WaitForSingleObject yourself.

User interaction in non-UI thread?

in my WPF - C# application, I have a time consuming function, which I execute with a BackgroundWorker. The job of this function is to add given data from a file into a database. Now and then, I need some user feedback, for example the data is already in the store and I want to ask the user, whether he wants to merge the data or create a new object or skip the data completely. Much like the dialog windows shows, if I try to copy a file to a location, where a file with the same name already exists.
The problem is, that I cannot call a GUI-window from a non GUI-thread. How could I implement this behavior?
Thanks in advance,
Frank
You could work with EventWaitHandle ou AutoResetEvent, then whenever you want to prompt the user, you could the signal UI, and then wait for the responde. The information about the file could be stored on a variable.
If possible... my suggestion is to architect your long running task into atomic operations. Then you can create a queue of items accessible by both your background thread and UI thread.
public class WorkItem<T>
{
public T Data { get; set; }
public Func<bool> Validate { get; set; }
public Func<T, bool> Action { get; set; }
}
You can use something like this class. It uses a queue to manage the execution of your work items, and an observable collection to signal the UI:
public class TaskRunner<T>
{
private readonly Queue<WorkItem<T>> _queue;
public ObservableCollection<WorkItem<T>> NeedsAttention { get; private set; }
public bool WorkRemaining
{
get { return NeedsAttention.Count > 0 && _queue.Count > 0; }
}
public TaskRunner(IEnumerable<WorkItem<T>> items)
{
_queue = new Queue<WorkItem<T>>(items);
NeedsAttention = new ObservableCollection<WorkItem<T>>();
}
public event EventHandler WorkCompleted;
public void LongRunningTask()
{
while (WorkRemaining)
{
if (_queue.Any())
{
var workItem = _queue.Dequeue();
if (workItem.Validate())
{
workItem.Action(workItem.Data);
}
else
{
NeedsAttention.Add(workItem);
}
}
else
{
Thread.Sleep(500); // check if the queue has items every 500ms
}
}
var completedEvent = WorkCompleted;
if (completedEvent != null)
{
completedEvent(this, EventArgs.Empty);
}
}
public void Queue(WorkItem<T> item)
{
// TODO remove the item from the NeedsAttention collection
_queue.Enqueue(item);
}
}
Your UI codebehind could look something like
public class TaskRunnerPage : Page
{
private TaskRunner<XElement> _taskrunner;
public void DoWork()
{
var work = Enumerable.Empty<WorkItem<XElement>>(); // TODO create your workItems
_taskrunner = new TaskRunner<XElement>(work);
_taskrunner.NeedsAttention.CollectionChanged += OnItemNeedsAttention;
Task.Run(() => _taskrunner.LongRunningTask()); // run this on a non-UI thread
}
private void OnItemNeedsAttention(object sender, NotifyCollectionChangedEventArgs e)
{
// e.NewItems contains items that need attention.
foreach (var item in e.NewItems)
{
var workItem = (WorkItem<XElement>) item;
// do something with workItem
PromptUser();
}
}
/// <summary>
/// TODO Use this callback from your UI
/// </summary>
private void OnUserAction()
{
// TODO create a new workItem with your changed parameters
var workItem = new WorkItem<XElement>();
_taskrunner.Queue(workItem);
}
}
This code is untested! But the basic principle should work for you.
Specifically to your case
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
Thread.Sleep(1000);
var a = Test1("a");
Thread.Sleep(1000);
var b = (string)Invoke(new Func<string>(() => Test2("b")));
MessageBox.Show(a + b);
}
private string Test1(string text)
{
if (this.InvokeRequired)
return (string)this.Invoke(new Func<string>(() => Test1(text)));
else
{
MessageBox.Show(text);
return "test1";
}
}
private string Test2(string text)
{
MessageBox.Show(text);
return "test2";
}
Test2 is a normal method which you have to invoke from background worker. Test1 can be called directly and uses safe pattern to invoke itself.
MessageBox.Show is similar to yourForm.ShowDialog (both are modal), you pass parameters to it (text) and you return value (can be a value of property of yourForm which is set when form is closed). I am using string, but it can be any data type obviously.
From the input of the answers here, I came to the following solution:
(Mis)Using the ReportProgress-method of the Backgroundworker in Combination with a EventWaitHandle. If I want to interact with the user, I call the ReportProgress-method and setting the background process on wait. In the Handler for the ReportProgress event I do the interaction and when finished, I release the EventWaitHandle.
BackgroundWorker bgw;
public MainWindow()
{
InitializeComponent();
bgw = new BackgroundWorker();
bgw.DoWork += new DoWorkEventHandler(bgw_DoWork);
bgw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bgw_RunWorkerCompleted);
bgw.WorkerReportsProgress = true;
bgw.ProgressChanged += new ProgressChangedEventHandler(bgw_ProgressChanged);
}
// Starting the time consuming operation
private void Button_Click(object sender, RoutedEventArgs e)
{
bgw.RunWorkerAsync();
}
// using the ProgressChanged-Handler to execute the user interaction
void bgw_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
UserStateData usd = e.UserState as UserStateData;
// UserStateData.Message is used to see **who** called the method
if (usd.Message == "X")
{
// do the user interaction here
UserInteraction wnd = new UserInteraction();
wnd.ShowDialog();
// A global variable to carry the information and the EventWaitHandle
Controller.instance.TWS.Message = wnd.TextBox_Message.Text;
Controller.instance.TWS.Background.Set();
}
}
void bgw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
MessageBox.Show(e.Result.ToString());
}
// our time consuming operation
void bgw_DoWork(object sender, DoWorkEventArgs e)
{
Thread.Sleep(2000);
// need 4 userinteraction: raise the ReportProgress event and Wait
bgw.ReportProgress(0, new UserStateData() { Message = "X", Data = "Test" });
Controller.instance.TWS.Background.WaitOne();
// The WaitHandle was released, the needed information should be written to global variable
string first = Controller.instance.TWS.Message.ToString();
// ... and again
Thread.Sleep(2000);
bgw.ReportProgress(0, new UserStateData() { Message = "X", Data = "Test" });
Controller.instance.TWS.Background.WaitOne();
e.Result = first + Controller.instance.TWS.Message;
}
I hope I did not overlooked some critical issues. I'm not so familar with multithreading - maybe there should be some lock(object) somewhere?

Windows 8 Store App Call with Initial Argument Parameters

On launch of my Win8 Store App I want to pass argument parameters.
I was looking at the following method that is called in the App class. Looks like it is passing arguments along, so my question is how do I pass arguments to "OnLaunched" ? Essentially when I run the app straight away from the Win8 Menu
protected override void OnLaunched(LaunchActivatedEventArgs e)
{
if (rootFrame.Content == null)
{
// When the navigation stack isn't restored navigate to the first page,
// configuring the new page by passing required information as a navigation
// parameter
rootFrame.Navigate(typeof(MainPage), e.Arguments);
}
}
These arguments can be passed in via a secondary tile that could be used to launch the app to a specified page during application launch.
I typically use a ViewManager to manage the view to be displayed based on these arguments.
App.cs
protected override async void OnLaunched(LaunchActivatedEventArgs args)
{
ApplicationData.Current.LocalSettings.Values[Constants.APP_PARAMETERS] = args.Arguments;
// Do not repeat app initialization when already running, just ensure that
// the window is active
if (args.PreviousExecutionState == ApplicationExecutionState.Running)
{
Window.Current.Activate();
await ViewManager.Instance.LaunchView();
return;
}
ViewManager:
public class ViewManager
{
#region Singleton
private ViewManager()
{
}
static ViewManager _viewManager = null;
public static ViewManager Instance
{
get
{
if (_viewManager == null)
{
_viewManager = new ViewManager();
}
return _viewManager;
}
}
#endregion
public async Task LaunchView()
{
bool displaySubheader = false;
var displayBackbutton = false;
var arguments = ApplicationData.Current.LocalSettings.Values[Constants.APP_PARAMETERS] as string;
var argumentsExist = !string.IsNullOrEmpty(arguments);
if (!argumentsExist)
{
await UIServices.Instance.Load(typeof(HomePage), null, displaySubheader, displayBackbutton);
}
else
{
displaySubheader = true;
displayBackbutton = false;
await UIServices.Instance.Load(typeof(GroupPage), arguments, displaySubheader, displayBackbutton);
var groupId = new Guid(arguments);
await ReadPost(groupId);
}
}

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