As windows phone 8 provides us with this method for programmatically terminate an app, will there be any issue while app submission if we use this in app for terminating a page while there is no backentry in the navigation history?
There won't be any issue in certification when using this call, but make sure you have saved all data in your app when calling this, because this call effectively kills your app immediately - ApplicationClosing even handler won't be raised after it!
Why would you call Application.Terminate when navigating back with an empty back stack? Just let the app close itself. Seems a bit pointless to me to overuse Application.Terminate().
I can't say much about the new Terminate method, but I do have an app (NOTE: Not a game) that does the following at certain points
private void Kill()
{
new Microsoft.Xna.Framework.Game().Exit();
}
This app passed certification without any problems. This was an app for both WP7 and WP8 so I did not have the ability to use Terminate().
Related
I have a Line-of-Business (LoB) Windows 8.1 Store application I developed for a client. The client side-loads it on several Windows 10 tablets. They use it in an environment where WiFi is spotty at best and they would like to get some sort of notification inside the app, regardless of what page they are on, notification that will let them know that they've lost connectivity to the network. I have created a method on my Web API that is not hitting the repository (database). Instead, it quickly returns some static information regarding my Web API, such as version, date and time of the invocation and some trademark stuff that I'm required to return. I thought of calling this method at precise intervals of time and when there's no response, assume that the Web API connectivity is lost. In my main page, the first one displayed when the application is started, I have the following stuff in the constructor of my view model:
_webApiStatusTimer = new DispatcherTimer();
_webApiStatusTimer.Tick += OnCheckWebApiStatusEvent;
_webApiStatusTimer.Interval = new TimeSpan(0, 0, 30);
_webApiStatusTimer.Start();
Then, the event handler is implemented like this:
private async void OnCheckWebApiStatusEvent(object sender, object e)
{
// stop the timer
_webApiStatusTimer.Stop();
// refresh the search
var webApiInfo = await _webApiClient.GetWebApiInfo();
// add all returned records in the list
if (webApiInfo == null)
{
var messageDialog = new MessageDialog(#"The application has lost connection with the back-end Web API!");
await messageDialog.ShowAsync();
// restart the timer
_webApiStatusTimer.Start();
}
}
When the Web API connection is lost, I get a nice popup message that informs me that the Web API is no longer available. The problem I have is that after a while, especially if I navigate away from the first page but not necessary, I get an UnauthorizedAccessException in my application.
I use the DispatcherTimer since my understanding is that this is compatible with
UI threads, but obviously, I still do something wrong. Anyone cares to set me on the right path?
Also, if you did something similar and found a much better approach, I'd love to hear about your solution.
Thanks in advance,
Eddie
First, If you are using Windows Store Apps, then you could possibly use a Background task to check poll for the status of the web api instead of putting this responsibility on your view model, its not the viewmodels concern
Second, if you are connecting from your Windows store app to your API then one successful authentication/ authorization for the first time, how and where do you store the token (assuming you are using token authentication). If you are (and ideally you should), is there a timer that you start which is set to the token expiration time? Is your local storage getting flushed somehow and loosing the aurthorization data?
Need more information.
I am quite new to windows 8 phone and I don't know all the life cycle methods and when what is called.
My problem is the following: I have a page that loads some data from the disk and when the user exits the program ( or suspends ) the data should be saved. As far as I can tell Page doesn't have an OnSuspending method only someOnNavigatingFrom, but those are not called when you just exit the program. So I read that I should use the OnSuspending in my App.xaml.cs, but this class doesn't have this data and also shouldn't have it, maybe only for OnSuspending. But I don't know how to get the data from my page in the OnSuspending method.
The OnSuspending event is quite fragile and you cannot expect it to run and save the state for a long time. But it depends on how long it would take for you to save. It doesn't even get triggered when you hit the home key while closing the app. If you really want an easy way. Just register a background task. While your app is in the background, the state can be saved and when you open the app again things are in place.
There are certain constraints With Background task as well, you cant do heavy lifting etc...here's a link you could use.
https://msdn.microsoft.com/en-us/library/windows/apps/xaml/hh977056.aspx
Implement an observer pattern (i.e. pub/sub) for your view-models to subscribe to in the event that your app is being suspended.
Your app handles the suspended event. As a result, publish a message for your view-models to respond to within your app's method handler for the suspended event.
You can use an EventAggregator or MessageBus (that I wrote).
in my windows phone 8 application i am using custom uri association to launch another application through my phone.
i.e
await Windows.System.Launcher.LaunchUriAsync(new Uri("sixtag:"));
but my app is not able to get certified for store because of this. the testing team tells that you app terminates unexpectedly while executing this.
now, i don't know how to deal with this.
is there any way to throw exception if the app which i am launching is not installed on phone ?
or i should try something else so my task gets accomplished and app gets certified for store as well.
You do not need to wrap your launch in try/catch or check for success as described in the other answers. As soon as you call LaunchUriAsync, the platform takes over and will automatically handle the possibility of no app being installed by asking the user if she wishes to search in the store.
A couple of things to double-check:
1) Ensure that you can successfully back into your app following the navigation to sixtag.
2) Ensure that your call to LaunchUriAsync is the direct result of a user action (eg. tapping a button)
try
{
await Windows.System.Launcher.LaunchUriAsync(new Uri("sixtag:"));
}
catch
{
MessageBox.Show("please install Sixtag from the app store","AppMissing", MessageBoxButton.OK);
}
you can perhaps display another button and on clicking directly navigate to the app store. See if this solves your problem. Do vote it up if it does :)
You are needed to handle that as shown here . Also Read out Remarks given there.
I'm trying to use OpenAs_RunDLLW to let the user select application he wants to open specific file with. But I don't want to really launch anything, just to let the user select and remember his choise so I can then open the file with this program later. In Windows XP, Vista and 7 OpenAs_RunDLLW finally used to call ShellExecuteExW, so I could temporary put the int 3 opcode at the beginning of this function, catch the exception and get all parameters passed to ShellExecuteExW. This was good and really worked.
But under Windows 8/8.1 it seems that OpenAs_RunDLLW does not call ShellExecuteExW, since the breakpoint is never hit. The selected app is launched instead. So, my question is - which API function does OpenAs_RunDLLW finally call to execute the program under Windows 8?
I believe that the shell now uses IAssocHandler::Invoke to open the item. However, you probably don't really care about that; what you want is a way to find out how to get the invocation handler.
For that, you want ShAssocEnumHandlers, which takes a file name extension and returns an association enumerator (that is, a function that will enumerate all the various applications that can open that extension).
On Windows Vista and later, use SHOpenWithDialog() instead of calling OpenAs_RunDLL(), and then use SHAssocEnumHandlers() to find out which handlers are registered and to invoke a particular handler when needed, instead of using ShellExecute().
I am developing a Windows Phone 8 application.
How can I exit or quit programmatically (through code) from my Windows Phone 8 app?
What are the various ways in which I can programmatically (through code) exit or quit from my Windows Phone 8 app?
In WP8 there's a new API which lets you terminate the application:
Application.Current.Terminate();
By calling the method your app will immediatelly terminate. However the Application_Closing event won't be called, and IsolatedStorageSettings.ApplicationSettings dictionary won't be automatically persisted.
So if you have data hanging around in IsolatedStorageSettings.ApplicationSettings that you don't want to lose then it's wise to save it:
IsolatedStorageSettings.ApplicationSettings.Save();
Application.Current.Terminate();
Also the method should not be misused. See http://msdn.microsoft.com/en-us/library/windowsphone/develop/system.windows.application.terminate(v=vs.105).aspx for more info for legitimate use cases.
while (((PhoneApplicationFrame)App.Current.RootVisual).CanGoBack)
{
((PhoneApplicationFrame)App.Current.RootVisual).RemoveBackEntry();
}
In Windows Phone 8.1, the method has been renamed to
Application.Current.Exit();