We Keep Coding

Issues resuming app with PickFolderAndContinue method

I am having issues resuming my app after utilizing the PickFolderAndContinue method. I've been trying to go off the directions from this MSDN sample. I haven't been able to figure out how to change the OnActivated method to return to my Settings page (the sample uses only the mainpage with different frames of content).
protected async override void OnActivated(IActivatedEventArgs e)
{
base.OnActivated(e);
ContinuationManager continuationManager = new ContinuationManager();
Frame rootFrame = CreateRootFrame();
await RestoreStatusAsync(e.PreviousExecutionState);
if (rootFrame.Content == null)
{
rootFrame.Navigate(typeof(SettingsPage));
}
var continuationEventArgs = e as IContinuationActivatedEventArgs;
if (continuationEventArgs != null)
{
// What do i do here to return to my settings page?
Frame scenarioFrame = SettingsPage.Current.FindName("ScenarioFrame") as Frame;
if (scenarioFrame != null)
{
// Call ContinuationManager to handle continuation activation
continuationManager.Continue(continuationEventArgs, scenarioFrame);
}
}
Window.Current.Activate();
}
Thanks.

When your OnActivated is called if you know you always want to go to the SettingsPage then all you need is this code:
Frame rootFrame = CreateRootFrame();
await RestoreStatusAsync(e.PreviousExecutionState);
if (rootFrame.Content == null)
{
rootFrame.Navigate(typeof(SettingsPage));
}
That code creates the applications root frame, and tells it to navigate to that specific page.
The code after this uses ContinuationManager. This is a mechanism set up to call into the page to let it know it is coming back from a AndContinue method. This will allow the page to do any functionality to occur for that Page.
FilePicker also has a ContinuationData property which you can set prior to calling the AndContinue method. This data is available in OnActivated via the IContinuationActivatedEventArgs.
This blog has a good description of the AndContinue Methods:
http://blogs.msdn.com/b/wsdevsol/archive/2014/05/08/using-the-andcontinue-methods-in-windows-phone-silverlight-8-1-apps.aspx

System.Reflection.TargetInvocationException

I just updated my phone to WP8.1 and I created an update for my app yesterday and removed and added a few functions and suddenly one page doesn't work and throws a System.Reflection.TargetInvocationException.
App.xaml.cs:
using System;
using System.Diagnostics;
using System.Resources;
using System.Windows;
using System.Windows.Markup;
using System.Windows.Navigation;
using Microsoft.Phone.Controls;
using Microsoft.Phone.Shell;
using Knowledge_Organizer.Resources;
namespace Knowledge_Organizer
{
public partial class App : Application
{
/// <summary>
/// Provides easy access to the root frame of the Phone Application.
/// </summary>
/// <returns>The root frame of the Phone Application.</returns>
public static PhoneApplicationFrame RootFrame { get; private set; }
/// <summary>
/// Constructor for the Application object.
/// </summary>
public App()
{
// Global handler for uncaught exceptions.
UnhandledException += Application_UnhandledException;
// Standard XAML initialization
InitializeComponent();
// Phone-specific initialization
InitializePhoneApplication();
// Language display initialization
InitializeLanguage();
// Show graphics profiling information while debugging.
if (Debugger.IsAttached)
{
// Display the current frame rate counters.
Application.Current.Host.Settings.EnableFrameRateCounter = true;
// Show the areas of the app that are being redrawn in each frame.
//Application.Current.Host.Settings.EnableRedrawRegions = true;
// Enable non-production analysis visualization mode,
// which shows areas of a page that are handed off to GPU with a colored overlay.
//Application.Current.Host.Settings.EnableCacheVisualization = true;
// Prevent the screen from turning off while under the debugger by disabling
// the application's idle detection.
// Caution:- Use this under debug mode only. Application that disables user idle detection will continue to run
// and consume battery power when the user is not using the phone.
PhoneApplicationService.Current.UserIdleDetectionMode = IdleDetectionMode.Disabled;
}
}
// Code to execute when the application is launching (eg, from Start)
// This code will not execute when the application is reactivated
private void Application_Launching(object sender, LaunchingEventArgs e)
{
}
// Code to execute when the application is activated (brought to foreground)
// This code will not execute when the application is first launched
private void Application_Activated(object sender, ActivatedEventArgs e)
{
}
// Code to execute when the application is deactivated (sent to background)
// This code will not execute when the application is closing
private void Application_Deactivated(object sender, DeactivatedEventArgs e)
{
}
// Code to execute when the application is closing (eg, user hit Back)
// This code will not execute when the application is deactivated
private void Application_Closing(object sender, ClosingEventArgs e)
{
}
// Code to execute if a navigation fails
private void RootFrame_NavigationFailed(object sender, NavigationFailedEventArgs e)
{
if (Debugger.IsAttached)
{
// A navigation has failed; break into the debugger
Debugger.Break();
}
}
// Code to execute on Unhandled Exceptions
private void Application_UnhandledException(object sender, ApplicationUnhandledExceptionEventArgs e)
{
if (Debugger.IsAttached)
{
// An unhandled exception has occurred; break into the debugger
Debugger.Break();
}
}
#region Phone application initialization
// Avoid double-initialization
private bool phoneApplicationInitialized = false;
// Do not add any additional code to this method
private void InitializePhoneApplication()
{
if (phoneApplicationInitialized)
return;
// Create the frame but don't set it as RootVisual yet; this allows the splash
// screen to remain active until the application is ready to render.
RootFrame = new PhoneApplicationFrame();
RootFrame.Navigated += CompleteInitializePhoneApplication;
// Handle navigation failures
RootFrame.NavigationFailed += RootFrame_NavigationFailed;
// Handle reset requests for clearing the backstack
RootFrame.Navigated += CheckForResetNavigation;
// Ensure we don't initialize again
phoneApplicationInitialized = true;
}
// Do not add any additional code to this method
private void CompleteInitializePhoneApplication(object sender, NavigationEventArgs e)
{
// Set the root visual to allow the application to render
if (RootVisual != RootFrame)
RootVisual = RootFrame;
// Remove this handler since it is no longer needed
RootFrame.Navigated -= CompleteInitializePhoneApplication;
}
private void CheckForResetNavigation(object sender, NavigationEventArgs e)
{
// If the app has received a 'reset' navigation, then we need to check
// on the next navigation to see if the page stack should be reset
if (e.NavigationMode == NavigationMode.Reset)
RootFrame.Navigated += ClearBackStackAfterReset;
}
private void ClearBackStackAfterReset(object sender, NavigationEventArgs e)
{
// Unregister the event so it doesn't get called again
RootFrame.Navigated -= ClearBackStackAfterReset;
// Only clear the stack for 'new' (forward) and 'refresh' navigations
if (e.NavigationMode != NavigationMode.New && e.NavigationMode != NavigationMode.Refresh)
return;
// For UI consistency, clear the entire page stack
while (RootFrame.RemoveBackEntry() != null)
{
; // do nothing
}
}
#endregion
// Initialize the app's font and flow direction as defined in its localized resource strings.
//
// To ensure that the font of your application is aligned with its supported languages and that the
// FlowDirection for each of those languages follows its traditional direction, ResourceLanguage
// and ResourceFlowDirection should be initialized in each resx file to match these values with that
// file's culture. For example:
//
// AppResources.es-ES.resx
// ResourceLanguage's value should be "es-ES"
// ResourceFlowDirection's value should be "LeftToRight"
//
// AppResources.ar-SA.resx
// ResourceLanguage's value should be "ar-SA"
// ResourceFlowDirection's value should be "RightToLeft"
//
// For more info on localizing Windows Phone apps see http://go.microsoft.com/fwlink/?LinkId=262072.
//
private void InitializeLanguage()
{
try
{
// Set the font to match the display language defined by the
// ResourceLanguage resource string for each supported language.
//
// Fall back to the font of the neutral language if the Display
// language of the phone is not supported.
//
// If a compiler error is hit then ResourceLanguage is missing from
// the resource file.
RootFrame.Language = XmlLanguage.GetLanguage(AppResources.ResourceLanguage);
// Set the FlowDirection of all elements under the root frame based
// on the ResourceFlowDirection resource string for each
// supported language.
//
// If a compiler error is hit then ResourceFlowDirection is missing from
// the resource file.
FlowDirection flow = (FlowDirection)Enum.Parse(typeof(FlowDirection), AppResources.ResourceFlowDirection);
RootFrame.FlowDirection = flow;
}
catch
{
// If an exception is caught here it is most likely due to either
// ResourceLangauge not being correctly set to a supported language
// code or ResourceFlowDirection is set to a value other than LeftToRight
// or RightToLeft.
if (Debugger.IsAttached)
{
Debugger.Break();
}
throw;
}
}
private void ApplicationBarIconButton_Click(object sender, EventArgs e)
{
}
private void ApplicationBarIconButton_Click_1(object sender, EventArgs e)
{
}
}
}
Error: > Knowledge Organizer.ni.DLL!Knowledge_Organizer.App.RootFrame_NavigationFailed(object sender, System.Windows.Navigation.NavigationFailedEventArgs e) Line 92 C#
// Code to execute if a navigation fails
private void RootFrame_NavigationFailed(object sender, NavigationFailedEventArgs e)
{
if (Debugger.IsAttached)
{
// A navigation has failed; break into the debugger
Debugger.Break();
}
}

EDIT.
Solution was extremely simple - the page.xaml.cs used 1 & 2 as reference when initialized the appbar instead of 0 & 1 - which caused it to not find the number 2 AppBarIconButton - that threw the exception. Solution:
// Initialize these so that we can edit them
deletenotesBtn = ApplicationBar.Buttons[0] as Microsoft.Phone.Shell.ApplicationBarIconButton;
addnoteBtn = ApplicationBar.Buttons[1] as Microsoft.Phone.Shell.ApplicationBarIconButton;

MonoTouch memory issue with Threading / Timers

I am having an issue with MonoTouch where UIViewControllers are remaining in-memory forever, even after they have been popped from the navigation stack.
I have a UINavigationController which contains a UIViewController with a button. Clicking the button pushes a custom UIViewController called ThreadingViewController onto the navigation stack.
The ThreadingViewController uses a NSTimer.CreateRepeatingScheduledTimer and a Thread to update the text of a label every one second.
When the user clicks "back" to pop back to the root view, the Mono Profiler says that my ThreadingViewController still exists in memory. The Profiler tells me it has something to do with NSAction and/or ThreadStart which has a reference to the ThreadingViewController, keeping it alive. I can see this by checking the "inverse references" checkbox in the profiler.
This means that if the user clicks backwards and forwards 100 times between the root ViewController and the custom ThreadingViewController, there will be 100 instances of this ViewController in memory. It isn't being garbage collected.
In ViewDidDisappear I have tried aborting the thread, setting it to null, to no avail.
What do I need to do to get this ThreadingViewController to be properly cleaned up / GC'ed by MonoTouch?
Here is the full (C# only) source code to reproduce the problem:
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using MonoTouch.Foundation;
using MonoTouch.UIKit;
using System.Threading;
namespace MemoryTests
{
[Register("AppDelegate")]
public partial class AppDelegate : UIApplicationDelegate
{
private UIWindow window;
private UINavigationController rootNavigationController;
private RootScreen rootScreen;
public override bool FinishedLaunching(UIApplication app, NSDictionary options)
{
window = new UIWindow(UIScreen.MainScreen.Bounds);
rootScreen = new RootScreen();
rootNavigationController = new UINavigationController(rootScreen);
window.RootViewController = rootNavigationController;
window.MakeKeyAndVisible();
return true;
}
}
public class RootScreen : UIViewController
{
private UIButton button;
public override void ViewDidLoad()
{
base.ViewDidLoad();
this.Title = "Root Screen";
// Add a button
button = new UIButton(UIButtonType.RoundedRect);
button.SetTitle("Click me", UIControlState.Normal);
button.Frame = new RectangleF(100, 100, 120, 44);
this.View.Add(button);
}
public override void ViewWillAppear(bool animated)
{
base.ViewWillAppear(animated);
button.TouchUpInside += PushThreadingViewController;
}
public override void ViewDidDisappear(bool animated)
{
base.ViewDidDisappear(animated);
button.TouchUpInside -= PushThreadingViewController;
}
private void PushThreadingViewController(object sender, EventArgs e)
{
var threadingViewController = new ThreadingViewController();
NavigationController.PushViewController(threadingViewController, true);
}
}
public class ThreadingViewController : UIViewController
{
private UILabel label;
private NSTimer timer;
private int counter;
public override void ViewDidLoad()
{
base.ViewDidLoad();
this.Title = "Threading Screen";
// Add a label
label = new UILabel();
label.Frame = new RectangleF(0f, 200f, 320f, 44f);
label.Text = "Count: 0";
this.View.Add(label);
// Start a timer
var timerThread = new Thread(StartTimer as ThreadStart);
timerThread.Start();
}
public override void ViewDidDisappear (bool animated)
{
base.ViewDidDisappear(animated);
timer.Dispose();
timer = null;
// Do I need to clean up more Threading things here?
}
[Export("StartTimer")]
private void StartTimer()
{
using (var pool = new NSAutoreleasePool())
{
timer = NSTimer.CreateRepeatingScheduledTimer(1d, TimerTicked);
NSRunLoop.Current.Run();
}
}
private void TimerTicked()
{
InvokeOnMainThread(() => {
label.Text = "Count: " + counter;
counter++;
});
}
}
}
Here is a screenshot of the profiler telling me that we have 3 instances of ThreadingViewController in memory:
Cheers.

I think the problem is here:
timer.Dispose();
Try changing it to:
timer.Invalidate();
NSTimer is the only thing here that uses an NSAction.
Also, I don't think this is very helpful:
var timerThread = new Thread(StartTimer as ThreadStart);
timerThread.Start();
Reasons:
It's not a background thread. Not sure how foreground .NET threads behave on iOS. My guess is, it never finishes.
You don't need to have a separate thread live all the time, within from you are starting the NSTimer. NSTimers are light, bulletproof and provide all the options you need. They work great even if you are starting them on the UI thread.
(Please ignore #2 above if you have another reason you are doing it this way, which is not directly visible from your code. But, nothing else comes to mind).
PS: I haven't tested your code above. But I'm 100% sure that you must Invalidate() NSTimers so that they stop running, when you no longer need them.

Anytime you connect a click handler such as:
button.TouchUpInside += PushThreadingViewController;
You must also disconnect it. I would suggest moving the line of code above to the ViewDidAppear override, and adding the line of code below to the ViewDidDisappear override:
button.TouchUpInside -= PushThreadingViewController;
I would also recommend that you check to see if threadingViewController is null and only creating a new instance if it is, before pushing it onto the navigation stack. That way it will use the same one each time if it hasn't been garbage collected yet.

Be careful with ViewDidDisappear. This method may called at any time your View-Controller yields control to another View-Controller (calling PresentViewController, invoking the sharing UI, display an iAd etc). If you only want to react when your View-Controller is removed from the navigation stack, I'd recommend this:
public override void DidMoveToParentViewController(UIViewController parent)
{
base.DidMoveToParentViewController(parent);
if(parent == null)
Cleanup();
}
Try invoking ReleaseOutlets() (generated from the Xamarin Studio XIB processor) from within your Cleanup() method in addition to unwiring the touch event handler improves the situation.

MediaElement Source cannot be set after SaveState/LoadState

(Note: All code has been severely simplified.)
Problem
MediaElement source not being set after Suspend/Resume. The CurrentState quickly changes to "Closed" after the source is set.
I am handling the MediaFailed event — it doesn't fire. I am also handling the MediaOpened event, which doesn't fire either.
Details
I have the following method which updates the MediaElement's Source. It works really well as long as the app is not trying to resume after having been Suspended.
private async void UpdateMediaElementSource(object sender, EventArgs e)
{
var videoSource = this.DefaultViewModel.CurrentSource; // a string
var file = await StorageFile.GetFileFromPathAsync(videoSource);
var videoStream = await file.OpenAsync(FileAccessMode.Read);
this.videoMediaElement.SetSource(videoStream, file.ContentType);
// The above line works many times as long as the app is not trying to Resume.
}
When the app is Suspended it calls the SaveState method:
protected async override void SaveState(Dictionary<String, Object> pageState)
{
pageState["MediaElementSource"] = this.DefaultViewModel.CurrentSource;
// I also made the videoStream global so I can dispose it — but no dice.
this.videoStream.Dispose();
this.videoStream = null;
}
When the app Resumes, it calls the LoadState method:
protected async override void LoadState(Object navigationParameter, Dictionary<String, Object> pageState)
{
string source = string.Empty;
if (pageState != null)
{
if (pageState.ContainsKey("MediaElementSource"))
{
source = (string)pageState["MediaElementSource"];
}
}
var document = PublicationService.GetDocument(this.currentDocumentIdNumber);
this.DefaultViewModel = new DocumentViewModel(document);
this.DefaultViewModel.CurrentMarkerSourceChanged += UpdateMediaElementSource;
if (!string.IsNullOrEmpty(source))
{
// This causes the UpdateMediaElementSource() method to run.
this.DefaultViewModel.CurrentSource = source;
}
}
I appreciate any help on this issue. Please let me know if you need more details.

So, it turns out that the mediaElement's Source was being set before it was added to the visual tree.
Usually, this is not an issue when doing this:
mediaElement.Source = whatever;
but it IS an issue when you do this:
mediaElement.SetSource(stream, MimeType);
Conclusion
Make sure that your MediaElement is part of the VisualTree when you call SetSource(...).
A simple way to get my above code to work is by adding a global bool that is set to true once the mediaElement.Loaded event has fired. Then, inside the code that calls SetSource(), wrap that in an if(_mediaElementLoaded) block.

Updating an ObservableCollection<T> asynchronously results in hangs, and no GUI update

I'm implementing a visual version of Tracert (as a learning exercise) in WPF where results go to a listbox. The issues are (1) the listbox bound to tracertDataView is not updating, but (2) my entire application hangs.
I'm sure #2 is a threading issue but I'm not sure how to correct it (in the right way). In addition I'm not sure my technique of updating / binding the results of "DoTrace" are correct.
Here is my datasource in App.xaml
<Window.Resources>
<CollectionViewSource
Source="{Binding Source={x:Static Application.Current}, Path=TracertResultNodes}"
x:Key="tracertDataView" />
</Window.Resources>
App.xaml.cs
public partial class App : Application
{
private ObservableCollection<TracertNode> tracertResultNodes = new ObservableCollection<TracertNode>();
public void AppStartup(object sender, StartupEventArgs e)
{
// NOTE: Load sample data does work correctly.. and displays on the screen.
// subsequent updates do not display
LoadSampleData();
}
private void LoadSampleData()
{
TracertResultNodes = new ObservableCollection<TracertNode>();
TracertNode t = new TracertNode();
t.Address = new System.Net.IPAddress(0x2414188f);
t.RoundTripTime = 30;
t.Status = System.Net.NetworkInformation.IPStatus.BadRoute;
TracertResultNodes.Add(t);
}
public ObservableCollection<TracertNode> TracertResultNodes
{
get { return this.tracertResultNodes; }
set { this.tracertResultNodes = value; }
}
}
Here is the MainWindow code
public partial class MainWindow : Window
{
CollectionViewSource tracertDataView;
TraceWrapper _tracertWrapper = null;
public MainWindow()
{
InitializeComponent();
_tracertWrapper = new TraceWrapper();
tracertDataView = (CollectionViewSource)(this.Resources["tracertDataView"]);
}
private void DoTrace_Click(object sender, RoutedEventArgs e)
{
((App)Application.Current).TracertResultNodes = _tracertWrapper.Results;
_tracertWrapper.DoTrace("8.8.8.8", 30, 50);
}
}
FYI Internal implementation Detail of instance object "traceWrapper.DoTrace"
/// <summary>
/// Trace a host. Note that this object internally calls the Async implementation of .NET's PING.
// It works perfectly fine in a CMD host, but not in WPF
/// </summary>
public ObservableCollection<TracertNode> DoTrace(string HostOrIP, int maxHops, int TimeOut)
{
tracert = new Tracert();
// The following is triggered for every host that is found, or upon timeout
// (up to 30 times by default)
AutoResetEvent wait = new AutoResetEvent(false);
tracert.waiter = wait;
tracert.HostNameOrAddress = HostOrIP;
tracert.Trace();
this.Results = tracert.NodeList;
while (tracert.IsDone == false)
{
wait.WaitOne();
IsDone = tracert.IsDone;
}
return tracert.NodeList;
}

I don't understand how u used AutoResetEvent, i guess it is not supposed to be used in this way :)
But since Trace run already in another thread, are you sure there is not an event "OnTracertComplete" or something like that in your Tracert class?
If there is not, why you just don't put a DispatchTimer into your application?
That timer would periodically poll until tracert.IsDone becomes true.
If you block the execution of the application thread until an operation completes, you block the execution of the window event loop so window will never be updated.
Another important thing: you cannot update ObservableCollections from another thread.
Be careful and be sure that everything that is updated in the WPF window is executed from the same thread of the window. Don't know what your Trace class do exactly, but your problem here seems to be of course the wait loop, that don't makes sense in a GUI application.
Use notification events or a timer to poll the result. A timer with 1 second resolution seems good to me for this particular implementation and the performance inpact is absolutely minimal.
This is a possible implementation if you are able to modify the Tracert class.
public delegate void TracertCallbacHandler(Tracert sender, TracertNode newNode);
public class Tracert
{
public event TracertCallbacHandler NewNodeFound;
public event EventHandler TracertCompleted;
public void Trace()
{
....
}
// This function gets called in tracert thread\async method.
private void FunctionCalledInThreadWhenPingCompletes(TracertNode newNode)
{
var handler = this.NewNodeFound;
if (handler != null)
handler(this, newNode);
}
// This function gets called in tracert thread\async methods when everything ends.
private void FunctionCalledWhenEverythingDone()
{
var handler = this.TracertCompleted;
if (handler != null)
handler(this, EventArgs.Empty);
}
}
And here is the code to run the tracert,
This is TracertWrapper.
// Keep the observable collection as a field.
private ObservableCollection<TracertNode> pTracertNodes;
// Keep the instance of the running tracert as a field, we need it.
private Tracert pTracert;
public bool IsTracertRunning
{
get { return this.pTracert != null; }
}
public ObservableCollection<TracertNode> DoTrace(string hostOrIP, int maxHops, int timeOut)
{
// If we are not already running a tracert...
if (this.pTracert == null)
{
// Clear or creates the list of tracert nodes.
if (this.pTracertNodes == null)
this.pTracertNodes = new ObservableCollection<TracertNode>();
else
this.pTracertNodes.Clear();
var tracert = new Tracert();
tracert.HostNameOrAddress = hostOrIP;
tracert.MaxHops = maxHops;
tracert.TimeOut = timeOut;
tracert.NewNodeFound += delegate(Tracert sender, TracertNode newNode)
{
// This method is called inside Tracert thread.
// We need to use synchronization context to execute this method in our main window thread.
SynchronizationContext.Current.Post(delegate(object state)
{
// This method is called inside window thread.
this.OnTracertNodeFound(this.pTracertNodes, newNode);
}, null);
};
tracert.TracertCompleted += delegate(object sender, EventArgs e)
{
// This method is called inside Tracert thread.
// We need to use synchronization context to execute this method in our main window thread.
SynchronizationContext.Current.Post(delegate(object state)
{
// This method is called inside window thread.
this.OnTracertCompleted();
}, null);
};
tracert.Trace();
this.pTracert = tracert;
}
return this.pTracertNodes;
}
protected virtual void OnTracertCompleted()
{
// Remove tracert object,
// we need this to let the garbage collector being able to release that objects.
// We need also to allow another traceroute since the previous one completed.
this.pTracert = null;
System.Windows.MessageBox.Show("TraceRoute completed!");
}
protected virtual void OnTracertNodeFound(ObservableCollection<TracertNode> collection, TracertNode newNode)
{
// Add our tracert node.
collection.Add(newNode);
}

The issue is that not only is the listbox not updating, but my entire application hangs.
This is probably due to the AutoResetEvent blocking in DoTrace. You explicitly call Wait.WaitOne(); on the event handle, but as far as I can tell, never Set() it. This will cause the application to hang forever as soon as you call Wait.WaitOne().
It sounds like tracert.Trace() is an asynchronous method. Does it include some form of callback/event to notify you upon completion? If so, you should use that, not poll in a loop, to determine when it's complete.

(1) the listbox bound to tracertDataView is not updating
You won't see the updates to your listbox, as you're assigning a new collection to the TracertResultNodes property, the binding in this case simply does not work, because a new collection was assigned.
In addition to ensuring that the collection is updated in the same thread as outlined by Salvatore below, you should only add or remove items from the existing collection, and NOT assign the new one generated by your DoTrace function.
private void DoTrace_Click(object sender, RoutedEventArgs e)
{
foreach(var traceNode in _tracertWrapper.Results)
{
((App)Application.Current).TracertResultNodes.Add(traceNode);
}
_tracertWrapper.DoTrace("8.8.8.8", 30, 50);
}
If you do assign a new one, then you'd need to implement INotifyPropertyChanged on your App class, am not sure how (or whether) that would work though (I have not tried this before).