How to handle back button pressed for UWP

Question

I used to use hardware button API in Windows Phone 8.1 XAML. However, in UWP some devices don't have back button. How do I adapt to the new app model?

Answer 1

you can use BackRequested event to handle back request:

SystemNavigationManager.GetForCurrentView().BackRequested += OnBackRequested;

if (App.MasterFrame.CanGoBack)
{
    rootFrame.GoBack();
    e.Handled = true;
}

Answer 2

Little bit explained answer. You can used SystemNavigationManager of Windows.UI.Core namespace

For Single Page

---

If you just want to handle navigation for single page. Follow the following steps

Step 1. Use namespace Windows.UI.Core

using Windows.UI.Core;

Step 2. Register back request event for current view. Best place for this is main constructor of class after InitializeComponent().

public MainPage()
{
    this.InitializeComponent();
    //register back request event for current view
    SystemNavigationManager.GetForCurrentView().BackRequested += MainPage_BackRequested;
}

Step 3. Handle BackRequested event

private void Food_BackRequested(object sender, BackRequestedEventArgs e)
{
    if (Frame.CanGoBack)
    {
        Frame.GoBack();
        e.Handled = true;
    }
}

For Complete Application at one place for single rootFrame

---

Best place for handling all backbutton for all Views is App.xaml.cs

Step 1. Use namespace Windows.UI.Core

using Windows.UI.Core;

Step 2. Register back request event for current view. Best place for this is OnLaunched just before Window.Current.Activate

protected override void OnLaunched(LaunchActivatedEventArgs e)
{
    ...
    SystemNavigationManager.GetForCurrentView().BackRequested += OnBackRequested;
    Window.Current.Activate();
}

Step 3. Handle BackRequested event

private void OnBackRequested(object sender, BackRequestedEventArgs e)
{
    Frame rootFrame = Window.Current.Content as Frame;
    if (rootFrame.CanGoBack)
    {
        rootFrame.GoBack();
        e.Handled = true;
    }
}

---

References- Handle back button pressed in UWP

Hope this is helpful to someone!

Answer 3

The above code is exactly correct but you have to add object of frame in rootFrame variable. Below are given:

private Frame _rootFrame;
 protected override void OnLaunched(LaunchActivatedEventArgs e)
 { 
        Frame rootFrame = Window.Current.Content as Frame;
        if (Window.Current.Content==null)
        {
            _rootFrame = new Frame();
        }
}

And pass this _rootFrame to OnBackRequested method. Like:

 private void OnBackRequested(object sender, BackRequestedEventArgs 
 {
       if (_rootFrame.CanGoBack)
       {
            _rootFrame.GoBack();
            e.Handled = true;
       }
 }