How to programmatically respond to Snap in Windows 8 Metro

Question

Is there a way to respond to Snap in C# in a Metro app? When one of the pages is snapped I need to show another one. My idea is to respond to snap by naviating to another page.

I found

var currentView = ApplicationLayout.GetForCurrentView();
currentView.LayoutChanged += new TypedEventHandler<ApplicationLayout, ApplicationLayoutChangedEventArgs>(currentView_LayoutChanged);

but it looks like it no longer works in Consumer Preview. Is there another way?

This is covered well in the Snap sample: http://code.msdn.microsoft.com/windowsapps/Snap-Sample-2dc21ee3 — Hans Passant, Apr 28 '12 at 16:04

score 24 · Answer 1 · answered Jun 14 '12 at 11:50

In Release Preview you need to react to a different event, again :) It's SizeChanged now, not ViewStateChanged.

Previously, your app would do something like this to handle view state changes:

using Windows.UI.ViewManagement;

// Register for the viewstatechanged event
ApplicationView.GetForCurrentView().ViewStateChanged += ViewStateChanged;    

private void ViewStateChanged(ApplicationView sender, ApplicationViewStateChangedEventArgs e)
{
     // Obtain view state from event payload
     ApplicationViewState myViewState = e.ViewState; 
}

Now apps should do this:

using Windows.UI.ViewManagement;

// Register for the window resize event
Window.Current.SizeChanged += WindowSizeChanged;     

private void WindowSizeChanged(object sender, Windows.UI.Core.WindowSizeChangedEventArgs e)
{
    // Obtain view state by explicitly querying for it
    ApplicationViewState myViewState = ApplicationView.Value;
}

More info here

B. Clay Shannon-B. Crow Raven · Answer 2 · 2012-11-07T22:16:58.033

Jowen had the answer, I'm just adding some more to the WindowSizeChanged code here:

    ApplicationViewState viewState = ApplicationView.Value;
    if (viewState == ApplicationViewState.Filled)
    {
        System.Diagnostics.Debug.WriteLine("viewState is Filled");
    }
    else if (viewState == ApplicationViewState.FullScreenLandscape)
    {
        System.Diagnostics.Debug.WriteLine("viewState is FullScreenLandscape");
    }
    else if (viewState == ApplicationViewState.Snapped)
    {
        System.Diagnostics.Debug.WriteLine("viewState is Snapped");
    }
    else if (viewState == ApplicationViewState.FullScreenPortrait)
    {
        System.Diagnostics.Debug.WriteLine("viewState is FullScreenPortrait");
    }
    else
    {
        System.Diagnostics.Debug.WriteLine("viewState is something unexpected");
    }

What I find a little surprising is that when I copied this placeholder code to another page, it gives the code a bounded rectangle and, since I did not have "using Windows.UI.ViewManagement;" yet, when I hovered over the unrecognized code, it asked "Import the file for the pasted code?" I guess it (I don't know if "it" is VS or Resharper) is keeping track of code that has pasted in, as it may be viewed with a rakishly angled or akimbo eyebrow.

'ApplicationViewState may be altered or unavailable for releases after Windows 8.1. Instead, query for window layout sizes directly.' AGAIN OUTDATED. — Jawahar, Jul 16 '15 at 07:27

score 5 · Accepted Answer · answered Apr 28 '12 at 15:58

5

In Consumer Preview you need to react to a different event. It's ViewStateChanged now, not LayoutChanged.

answered Apr 28 '12 at 15:58

Kate Gregory

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6

This answer is outdated. Check out my post below for Release Preview – Jowen Jun 14 '12 at 11:57
1

to be fair, it is not wrong FOR CONSUMER PREVIEW which is the first three words of the answer. It is not right for the current version, but that's not the same as being wrong. – Kate Gregory Oct 15 '13 at 16:04

How to programmatically respond to Snap in Windows 8 Metro

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