Develop Reference

Bring the UWP app to the front of current window

How can i use
await Windows.System.Launcher.LaunchUriAsync(new Uri("protocol://"));
to navigate to specific view of uwp application.
Is there any way to bring the app in front of the screen, if app was minimized or hidden behind other apps?
Thanks in advance

How can i use await Windows.System.Launcher.LaunchUriAsync(new Uri("protocol://")); to navigate to specific view of uwp application
For this, firstly you need to add the Protocol declaration in your Package.appxmanifest file . (Go to declarations tab and add Protocol from the available protocols). ( MSDN Doc )
Here i am using "app-protocol" as the protocol name.
Once this is done, you need to override the OnActivated() method in your App.xaml.cs. This method will be called when the app is launched using the protocol.
The arguments that we pass when calling the protocol can be retrieved here and based on that you can show your page or maybe pass that parameter to your page and let it handle the navigation .
For instance, if our Uri is app-protocol:login?param1=true, when you receive the ProtocolActivatedEventArgs eventArgs in the onActivated() method you will have access to the whole Uri.
You can use eventArgs.Uri to access all the Uri properties.
In any case your code should look something like this :
C#
protected override void OnActivated(IActivatedEventArgs args)
{
if (args.Kind == ActivationKind.Protocol)
{
ProtocolActivatedEventArgs eventArgs = args as ProtocolActivatedEventArgs;
// Get the root frame
Frame rootFrame = Window.Current.Content as Frame;
// Do not repeat app initialization when the Window already has content,
// just ensure that the window is active
if (rootFrame == null)
{
// Create a Frame to act as the navigation context and navigate to the first page
rootFrame = new Frame();
rootFrame.NavigationFailed += OnNavigationFailed;
if (args.PreviousExecutionState == ApplicationExecutionState.Terminated)
{
//TODO: Load state from previously suspended application
}
// Place the frame in the current Window
Window.Current.Content = rootFrame;
}
//URI : app-protocol:login?param1=true
//Logic for showing different pages/views based on parameters passed
if (eventArgs.Uri.PathAndQuery != string.Empty)//PathAndQuery:login?param1=true
{
var absolutePath = eventArgs.Uri.AbsolutePath;//AbsolutePath:login
if (absolutePath.Equals("login"))
{
rootFrame.Navigate(typeof(LoginPage));
}
else
{
rootFrame.Navigate(typeof(MainPage));
}
}
else
{
rootFrame.Navigate(typeof(MainPage));
}
}
// Ensure the current window is active
Window.Current.Activate();
}
Is there any way to bring the app in front of the screen, if app was minimized or hidden behind other apps?
We are calling Window.Current.Activate(); to ensure this.

To bring any UWP window to the front use this snippet (works if window with given viewId was already created and is either minimized or behind other windows:
private async Task TryActivateViewAsync(viewId)
{
if (Window.Current.Dispatcher != null)
{
await Window.Current.Dispatcher.RunAsync(CoreDispatcherPriority.Normal, async () =>
{
if (await ApplicationViewSwitcher.TryShowAsStandaloneAsync(viewId))
{
await ApplicationViewSwitcher.SwitchAsync(viewId);
}
});
}
}
Just as a reminder, viewId is an Identifier of a window which you can get when you create that window using:
var coreView = CoreApplication.CreateNewView(); // creates new view
await coreView.Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
{
_someViewId = ApplicationView.GetForCurrentView().Id; // gets that view's id
}

(UWP) Hardware Back Press work correctly in mobile but error with PC

In my UWP app when i click on mobile back button app get close, so add this code in app.xaml.cs
private async void HardwareButtons_BackPressed(object sender, BackPressedEventArgs e)
{
e.Handled = true;
Frame rootFrame = Window.Current.Content as Frame;
if (rootFrame.CanGoBack && rootFrame != null)
{
rootFrame.GoBack();
}
else
{
var msg = new MessageDialog("Confirm Close! \nOr Press Refresh Button to Go Back");
var okBtn = new UICommand("OK");
var cancelBtn = new UICommand("Cancel");
msg.Commands.Add(okBtn);
msg.Commands.Add(cancelBtn);
IUICommand result = await msg.ShowAsync();
if (result != null && result.Label == "OK")
{
Application.Current.Exit();
}
}
}
and
public App()
{
this.InitializeComponent();
this.Suspending += OnSuspending;
/* Because of this line my app work on mobile great but when
when i debug on pc it through exception "show in image" */
HardwareButtons.BackPressed += HardwareButtons_BackPressed;
}
After Done all this code when i debug app on phone, app successfully run -
Mobile Debuging:
But when debug in pc with same code, it show this error- PC Debuging:
when i remove HardwareButtons.BackPressed += HardwareButtons_BackPressed; then issue with pc debugging resolved but in mobile debuging back button again is not work.

The reason is that HardwareButtons API is not the universal solution for handling the back button. This API is available only in the Mobile extension SDK and trying to invoke it on other SKU will cause this exception, because the type is not available.
To enable the same functionality on all systems, you will need to use the new universal back button event:
SystemNavigationManager.GetForCurrentView().BackRequested += BackButtonHandler;
This will work the same on phone, PC, tablets,Xbox One, Surface Hub and HoloLens.
On PC this button is not shown by default, so you have to display it manually or create your own. To show the Back button in window's title bar, use:
SystemNavigationManager.GetForCurrentView().AppViewBackButtonVisibility =
AppViewBackButtonVisibility.Visible;
It is recommended that you hide this button once Frame.CanGoBack is false, because in that case the button is no longer useful. You should do this after each navigation of the frame. Best place to do this is when setting up the root frame in App.xaml.cs:
Frame rootFrame = Window.Current.Content as Frame;
rootFrame.Navigated += UpdateAppViewBackButton;
Now the handler could look like this:
private void UpdateAppViewBackButton( object sender, NavigationEventArgs e )
{
Frame frame = (Frame) sender;
var systemNavigationManager = SystemNavigationManager.GetForCurrentView();
systemNavigationManager.AppViewBackButtonVisibility =
frame.CanGoBack ? AppViewBackButtonVisibility.Visible :
AppViewBackButtonVisibility.Collapsed;
}
On Application close
I have also noticed that you are using Application.Current.Exit(); to exit the app. This is however not recommended. Once the user chooses OK in the dialog, you should rather set the e.Handled = false and let the system handle the app close manually. This will ensure the app suspension will run as expected and the app will stay in memory if the system has enough resources and will then launch faster again. Application.Current.Exit() kills the application and it is not recommended for UWP apps.
One thing to remember is that on Desktop, there is currently no way to catch the user clicking the close button in the app's title bar, so your confirmation dialog will not display in that case unfortunately.

How to set a "First-Launch-View" in C#

I searched everywhere, but i can't find a tutorial for my problem. I want to set an page to be shown, when the App is launched for the first time. something like th:
First launch:
Greeting.xaml>Setting.xaml>MainPage.xaml
Regular launch goes directly to MainPage.
how can i do this?
I didn't mean a Splashscreen, I mean a page, which is shown only the first time you launch the App, something like a little tutorial.

Your typical template-generated App.xaml.cs has something like this in its OnLaunched method:
if (rootFrame.Content == null)
{
rootFrame.Navigate(typeof(MainPage), e.Arguments);
}
This is where you navigate to your first page. To special-case a first run, do something like this instead:
if (rootFrame.Content == null)
{
IPropertySet roamingProperties = ApplicationData.Current.RoamingSettings.Values;
if (roamingProperties.ContainsKey("HasBeenHereBefore"))
{
// The normal case
rootFrame.Navigate(typeof(MainPage), e.Arguments);
}
else
{
// The first-time case
rootFrame.Navigate(typeof(GreetingsPage), e.Arguments);
roamingProperties["HasBeenHereBefore"] = bool.TrueString; // Doesn't really matter what
}
}
The greetings page should then navigate to your settings page, which should navigate to your main page.
And by using the roaming settings, the user won't see the first-time screen when she logs in to a different machine.

You can set the "first" page within the App.xaml.cs. Search for the OnLaunched void and change rootFrame.Navigate(typeof(MainPage)); to rootFrame.Navigate(typeof(Greeting)); or whtatever you like to call it.
The next step would be to check if the app launches for the first time. You can set an app setting to do that.
1. create the OnnavigatedTo void for your Greeting.xaml (just type "protected override void onna", IntelliSense will suggest it to you) and make is asynchron by inserting "async" after "protected", 2. use this code:
if (ApplicationData.Current.LocalSettings.Values.ContainsKey("isFirstLaunch"))
{
// if that's the first launch, stay, otherwise navigate to Settings.xaml
if (!(bool)ApplicationData.Current.LocalSettings.Values["isFirstLaunch"])
{
await Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () => Frame.Navigate(typeof(Settings)));
}
}
else
{
ApplicationData.Current.LocalSettings.Values["isFirstLaunch"] = false;
}
I haven't tested the code but it should work. If it doesn't, just ask me.
Edit: here's a much better solution :D https://stackoverflow.com/a/35176403/3146261

I just wanted a Disclaimer to be accepted via a MessageBox
IPropertySet roamingProperties = ApplicationData.Current.RoamingSettings.Values;
if (!roamingProperties.ContainsKey("DisclaimerAccepted"))
{
var dialog = new MessageDialog(strings.Disclaimer);
dialog.Title = "Disclaimer";
dialog.Commands.Clear();
dialog.Commands.Add(new UICommand { Label = "Accept", Id = 0 });
dialog.Commands.Add(new UICommand { Label = "Decline", Id = 1 });
var result = await dialog.ShowAsync();
if ((int)result.Id == 1)
Application.Current.Exit();
roamingProperties["DisclaimerAccepted"] = bool.TrueString;
}
I placed it in App.xaml.cs inside of:
if (e.PrelaunchActivated == false)
{
<Inside here>
if (rootFrame.Content == null)
{
}

Set start page in Windows Phone 8.1 universal app

I need to change start page in my app depending on logged user or not. In Silverlight 8.1 version all what I need to do is delete starting page in manifest file and in App.xaml.cs:
private void Application_Launching(object sender, LaunchingEventArgs e)
{
Uri uriMain = new Uri("/PivotPage.xaml", UriKind.Relative);
Uri uriLogin = new Uri("/MainPage.xaml", UriKind.Relative);
var settings = IsolatedStorageSettings.ApplicationSettings;
if (!settings.Contains("user_id"))
{
RootFrame.Navigate(uriLogin);
}
else
{
RootFrame.Navigate(uriMain);
}
}
But in universal version I can't figure out how can I do it. What I need to do to achive this in WP 8.1universal app?
EDIT:
Found a duplicate Change default startup page for windows phone 8.1 app, sorry

In App.xaml.cs look for
protected override void OnLaunched(LaunchActivatedEventArgs e)
{
// ...
// launch codes
// insert here
// Ensure the current window is active
Window.Current.Activate();
}
My launch code detects to see if they're on the Phone or not, so I have a starting page that is
different for each platform
#if WINDOWS_PHONE_APP
if (!rootFrame.Navigate(typeof(PhonePage), e.Arguments))
{
throw new Exception("Failed to create initial page");
}
#endif
#if WINDOWS_APP
if (!rootFrame.Navigate(typeof(DesktopPage), e.Arguments))
{
throw new Exception("Failed to create initial page");
}
#endif

Windows Phone 8.1 check if password set else load new page

I Have a very similar situation to this guys question in that I have a Login Page which is my MainPage.xaml file but I have another page called SetPassword.xaml that I want to load if a user has not set a password yet. Essentially this is the first time that the App loads after it has been installed.
I've spent hours on SO trying various different solutions (including the one I linked to) but I'm just not getting anywhere and it seems that many of the solutions are either for WP7 or WP8 and nothing similar has been solved for the new WP8.1.
This is the basic check, using Windows.Storage that I'm doing to see if a password has been set or not.
Windows.Storage.ApplicationDataContainer localSettings = Windows.Storage.ApplicationData.Current.LocalSettings;
Windows.Storage.StorageFolder localFolder = Windows.Storage.ApplicationData.Current.LocalFolder;
if (localSettings.Values["myPassword"] == null)
{
Debug.WriteLine("Password not set");
this.Frame.Navigate(typeof(SetPassword));
}
else
{
Debug.WriteLine("Password is set, continuing as normal");
}
If I add this to public MainPage() class I have no problem in the app returning "Password is not set" in the debug messages however the this.frame.Navigate(typeof(SetPassword)) navigation never loads the SetPassword view.
I have also tried this method in the OnNavigatedTo with exactly the same results.
In my App.xaml file I've also tried a number of different methods, again, with the same results. I can get the debug message but not the navigation I'm looking for. I looked at implementing a method on Application_Launching over here as well as implementing conditional navigation on RootFrame.Navigating+= RootFrameOnNavigating; over here but clearly I am missing something.
Hopefully you smarter people can help me get my navigation working based on a conditional value?

The solution was simple. To do the navigation I could have done it in either App or MainPage as per my question but the reason the navigation wasn't working was because I was trying to navigate to SetPassword.xaml which was a <ContentDialog> instead of a <Page>.
I feel embarrassed actually that I didn't even check that but hopefully if this happens to someone else they can check that they're actually trying to navigate to a Page and not any other type of element. How sadly foolish of me!
EDIT:
Here's what my OnLaunched in the App.xaml file looks like where I can now do my check and redirect to a different page based on the value being set.
protected override void OnLaunched(LaunchActivatedEventArgs e)
{
Frame rootFrame = Window.Current.Content as Frame;
if (rootFrame == null)
{
rootFrame = new Frame();
rootFrame.CacheSize = 1;
Window.Current.Content = rootFrame;
// The following checks to see if the value of the password is set and if it is not it redirects to the save password page - else it loads the main page.
Windows.Storage.ApplicationDataContainer localSettings = Windows.Storage.ApplicationData.Current.LocalSettings;
Windows.Storage.StorageFolder localFolder = Windows.Storage.ApplicationData.Current.LocalFolder;
if (localSettings.Values["myPassword"] == null)
{
rootFrame.Navigate(typeof(SetPassword));
}
else
{
rootFrame.Navigate(typeof(MainPage));
}
}
if (rootFrame.Content == null)
{
if (rootFrame.ContentTransitions != null)
{
this.transitions = new TransitionCollection();
foreach (var c in rootFrame.ContentTransitions)
{
this.transitions.Add(c);
}
}
rootFrame.ContentTransitions = null;
rootFrame.Navigated += this.RootFrame_FirstNavigated;
if (!rootFrame.Navigate(typeof(MainPage), e.Arguments))
{
throw new Exception("Failed to create initial page");
}
}
Window.Current.Activate();
}