Suspend & Resume for MediaCapture

Question

I have a UWP app which uses a MediaCapture & CaptureElement to preview the camera. I am unsure what to do to handle suspending & resuming of the app to stop the camera when suspending & start it when resuming. Because the Suspending & Resuming events are part of the Application class (not the Page class), I cannot access my MediaCapture & CaptureElement from those handlers. What should I do?

Answer 1

Hello,​

Welcome to our Microsoft Q&A platform!

You have two ways to achieve The way to handle properties inside the page in the application lifecycle event.

(Take MainPage as an example)

1. Registering Application Lifecycle Events in a Page

public MainPage()
{
    this.InitializeComponent();
    Application.Current.Suspending += Current_Suspending;
    Application.Current.Resuming += Current_Resuming;
}

private void Current_Resuming(object sender, object e)
{
    // Because it is a method registered in the Page, you can access the properties in the Page
}

private void Current_Suspending(object sender, Windows.ApplicationModel.SuspendingEventArgs e)
{
    // Because it is a method registered in the Page, you can access the properties in the Page
}

2. Create an accessible Page instance and access it in the App class

MainPage

public static MainPage Current;
public MainPage()
{
    this.InitializeComponent();
    Current = this;
}

App

public App()
{
    this.InitializeComponent();
    this.Suspending += App_Suspending;
    this.Resuming += App_Resuming;
}

private void App_Resuming(object sender, object e)
{
    if (MainPage.Current != null)
    {
        var capture = MainPage.Current._capture;
        // do other things
    }
}
private void App_Suspending(object sender, SuspendingEventArgs e)
{
    var deferral = e.SuspendingOperation.GetDeferral();
    if(MainPage.Current != null)
    {
        var capture = MainPage.Current._capture;
        // do other things
    }
    deferral.Complete();
}

Thanks