Develop Reference

Check if window is minimized in UWP

I am developing a UWP application for Windows 10. I want to show a message dialog box when user reduces the size of the window. As of now, I have tried to implement the feature using this link. My purpose is being fulfilled here except the message dialog appears when user either minimizes the window or changes its size. I have also attached the code snippet below. Thank you.
private async void CoreWindow_SizeChanged(Windows.UI.Core.CoreWindow sender, Windows.UI.Core.WindowSizeChangedEventArgs args)
{
var appView = ApplicationView.GetForCurrentView();
MessageDialog messageDialog = new MessageDialog("");
if (!appView.IsFullScreen)
{
if (!msgboxshown)
{
messageDialog = new MessageDialog("To run the application smoothly, please maximize the window.");
msgboxshown = true;
await messageDialog.ShowAsync();
msgboxshown = false;
}
}
args.Handled = true;
}

My purpose is being fulfilled here except the message dialog appears when user either minimizes the window or changes its size.
When app minimizes, it will invoke EnteredBackground event, you could detect it and show your message dialog.
public App()
{
this.InitializeComponent();
this.Suspending += OnSuspending;
this.EnteredBackground += App_EnteredBackground;
}
private async void App_EnteredBackground(object sender, EnteredBackgroundEventArgs e)
{
var messageDialog = new MessageDialog("To run the application smoothly, please maximize the window.");
await messageDialog.ShowAsync();
}
Update
As #Raymond Chen said, it looks os bug. So please use the above methods with caution.

voice command to capture photo

I use Windows.Media.Capture.MediaCapture in my Windows Phone 8.1 app to capture a photo. Instead of a button, I'd like to trigger the photo capturing process by a voice command (for example, if the user says 'cheese'). How can I detect such a voice command?

You can use the SpeechRecognizer class.
Here's a sample from MSDN:
private async void StartRecognizing_Click(object sender, RoutedEventArgs e)
{
// Create an instance of SpeechRecognizer.
var speechRecognizer = new Windows.Media.SpeechRecognition.SpeechRecognizer();
// Compile the dictation grammar by default.
await speechRecognizer.CompileConstraintsAsync();
// Start recognition.
Windows.Media.SpeechRecognition.SpeechRecognitionResult speechRecognitionResult = await speechRecognizer.RecognizeWithUIAsync();
// Do something with the recognition result.
var messageDialog = new Windows.UI.Popups.MessageDialog(speechRecognitionResult.Text, "Text spoken");
await messageDialog.ShowAsync();
}

SystemMediaTransportControls is not appearing in WP 8.1

I have been in a headache to display SystemMediaTransportControls in my wp8.1 app, unfortunately it doesn't work.
Here is the scenario, I have added Windows Phone App Project and then Windows Runtime Component (Windows Phone). I referenced the Runtime Component in My probject and then in the manifest added Audio as a Background Task.
Everything seems to work fine, the media is played in the background, but the SystemMediaTransportControls are not displayed. Below is my code for Run method in my BackgroundTask
public void Run(IBackgroundTaskInstance taskInstance)
{
Debug.WriteLine("Background Audio Task " + taskInstance.Task.Name + " starting...");
taskInstance.Canceled += TaskInstance_Canceled;
//taskInstance.Task.Completed += Taskcompleted;
systemmediatransportcontrol = SystemMediaTransportControls.GetForCurrentView();
systemmediatransportcontrol.ButtonPressed += systemmediatransportcontrol_ButtonPressed;
systemmediatransportcontrol.PropertyChanged += systemmediatransportcontrol_PropertyChanged;
systemmediatransportcontrol.IsEnabled = true;
systemmediatransportcontrol.IsPauseEnabled = true;
systemmediatransportcontrol.IsPlayEnabled = true;
systemmediatransportcontrol.IsNextEnabled = true;
systemmediatransportcontrol.IsPreviousEnabled = true;
BackgroundMediaPlayer.Current.CurrentStateChanged += Current_CurrentStateChanged;
BackgroundMediaPlayer.MessageReceivedFromForeground += BackgroundMediaPlayer_MessageReceivedFromForeground;
Debug.WriteLine(systemmediatransportcontrol.IsEnabled.ToString());
ValueSet message = new ValueSet();
message.Add("backgroundStarted", "1");
BackgroundMediaPlayer.SendMessageToForeground(message);
BackgroundTaskStarted.Set();
deferral = taskInstance.GetDeferral();
}
It has been two days working in this problem and it has given me a lot of headache. The question is, why SystemMediaTransportControls is not displayed?

Use SystemMediaTransportControls.DisplayUpdater to set the MusicProperties. MusicProperties is of type MusicDisplayProperties and include properties such as the song title and the song artist.
Update this on track change:
systemmediatransportcontrol.PlaybackStatus = MediaPlaybackStatus.Playing;
systemmediatransportcontrol.DisplayUpdater.Type = MediaPlaybackType.Music;
systemmediatransportcontrol.DisplayUpdater.MusicProperties.Title = "<Track_Name>";
systemmediatransportcontrol.DisplayUpdater.MusicProperties.Artist = "<Artist_Name>";
systemmediatransportcontrol.DisplayUpdater.Update();

Windows Phone Toast Notification Not Shown [duplicate]

In my application I want to notify the user with the ShellToast.
Just by running...
var toast = new ShellToast
{
Title = "Nom nom nom!",
Content = "More! More! Keep feeding me!",
};
toast.Show();
...makes nothing happen, and as I understand it needs to be run from a ScheduledTaskAgent. But how do I run this on command, and make sure it only run once?

You can't use a ShellToast while the app is the foreground app. It's meant to be invoked from a background service while the app isn't the foreground app.
If you want to have a UX similar to that of ShellToast use the Coding4fun toolkit ToastPrompt control. Here's a code snippet showing how to use it:
private void ToastWrapWithImgAndTitleClick(object sender, RoutedEventArgs e)
{
var toast = GetToastWithImgAndTitle();
toast.TextWrapping = TextWrapping.Wrap;
toast.Show();
}
private static ToastPrompt GetToastWithImgAndTitle()
{
return new ToastPrompt
{
Title = "With Image",
TextOrientation = System.Windows.Controls.Orientation.Vertical,
Message = LongText,
ImageSource = new BitmapImage(new Uri("../../ApplicationIcon.png", UriKind.RelativeOrAbsolute))
};
}
Running this code snippet shows the following:

Just a small update: using ShellToast when the app is in foreground, is now possible, when using Windows Phone 8 Update 3. Though, they are obscured by other activity such as a phone call or the lock screen. Source

How can I create a shelltoast?

In my application I want to notify the user with the ShellToast.
Just by running...
var toast = new ShellToast
{
Title = "Nom nom nom!",
Content = "More! More! Keep feeding me!",
};
toast.Show();
...makes nothing happen, and as I understand it needs to be run from a ScheduledTaskAgent. But how do I run this on command, and make sure it only run once?

You can't use a ShellToast while the app is the foreground app. It's meant to be invoked from a background service while the app isn't the foreground app.
If you want to have a UX similar to that of ShellToast use the Coding4fun toolkit ToastPrompt control. Here's a code snippet showing how to use it:
private void ToastWrapWithImgAndTitleClick(object sender, RoutedEventArgs e)
{
var toast = GetToastWithImgAndTitle();
toast.TextWrapping = TextWrapping.Wrap;
toast.Show();
}
private static ToastPrompt GetToastWithImgAndTitle()
{
return new ToastPrompt
{
Title = "With Image",
TextOrientation = System.Windows.Controls.Orientation.Vertical,
Message = LongText,
ImageSource = new BitmapImage(new Uri("../../ApplicationIcon.png", UriKind.RelativeOrAbsolute))
};
}
Running this code snippet shows the following:

Just a small update: using ShellToast when the app is in foreground, is now possible, when using Windows Phone 8 Update 3. Though, they are obscured by other activity such as a phone call or the lock screen. Source