Re-imagining the behavior to show the Windows Phone 7 camera as background - Init

<body> <h1>Re-imagining the behavior to show the Windows Phone 7 camera as background</h1> <p><a href="http://feedads.g.doubleclick.net/~a/d1xnH5uSCSsNI2gpV0_a_ajNCg8/0/da"><img src="http://feedads.g.doubleclick.net/~a/d1xnH5uSCSsNI2gpV0_a_ajNCg8/0/di" border="0" ismap="true"></img></a><br/> <a href="http://feedads.g.doubleclick.net/~a/d1xnH5uSCSsNI2gpV0_a_ajNCg8/1/da"><img src="http://feedads.g.doubleclick.net/~a/d1xnH5uSCSsNI2gpV0_a_ajNCg8/1/di" border="0" ismap="true"></img></a></p><p>This blog turns out not only to be a collection of how-to samples but also a record of my evolution as a <a href="http://www.microsoft.com/windowsphone/" target="_blank">Windows Phone 7</a> developer. At the end of my previous post, <a href="http://dotnetbyexample.blogspot.com/2011/11/safe-event-detachment-base-class-for.html">Safe event detachment base class for Windows Phone 7 behaviors</a>, I promised a usage example and I decided to re-implement the <a href="http://dotnetbyexample.blogspot.com/2011/10/behavior-to-show-windows-phone-7-camera.html">behavior to show the Windows Phone 7 camera as background</a> using the SafeBehavior as a base class. This makes the code considerable easier.</p> <p>The base setup of the re-implemented behavior is pretty simple:</p><pre style="font-size: 12px">using System.Windows.Controls; using System.Windows.Media; using System.Windows.Navigation; using Microsoft.Devices; using Microsoft.Phone.Controls; namespace Wp7nl.Behaviors { /// <summary> /// A behavior that shows a camera view on the background of a panel /// </summary> public class CameraViewBackgroundBehavior : SafeBehavior<Panel> { private PhotoCamera camera; private VideoBrush backgroundBrush; public CameraViewBackgroundBehavior() { ListenToPageBackEvent = true; } } }</pre> <p>Note this behavior needs to detect the user navigating back to the page – this in necessary because we need to do something with the camera.</p> <p>In stead of all the song and dance for attaching and detaching events using the <a href="http://www.schaikweb.net/dotnetbyexample/beh.zip" target="_blank">snippet</a> I published earlier, it’s now a matter of overriding the OnSetup and OnCleanup methods to initialize the camera:</p><pre style="font-size: 12px">protected override void OnSetup() { if (camera == null) { camera = new PhotoCamera(); ParentPage.OrientationChanged += ParentPageOrientationChanged; } // Create a video brush with the right parameters backgroundBrush = new VideoBrush { Stretch = Stretch.UniformToFill, AlignmentX = AlignmentX.Left, AlignmentY = AlignmentY.Top }; // Set the video brush to the background of the panel // and and do an initial display AssociatedObject.Background = backgroundBrush; backgroundBrush.SetSource(camera); SetVideoOrientation(ParentPage.Orientation); } protected override void OnCleanup() { ParentPage.OrientationChanged -= ParentPageOrientationChanged; camera.Dispose(); camera = null; }</pre> <p>This behavior also needs to do some action when the user actually navigates back to the page, which you can do by override the OnParentPageNavigated method - in this case, re-initializing the whole behavior</p><pre style="font-size: 12px">/// <summary> /// Fired whe page navigation happens /// </summary> /// <param name="sender"></param> /// <param name="e"></param> protected override void OnParentPageNavigated(object sender, NavigationEventArgs e) { // Re-setup when this page is navigated BACK to if( IsNavigatingBackToBehaviorPage(e)) { if (camera != null) { OnCleanup(); OnSetup(); } } }</pre> <p>The actual implementation of showing the camera background has hardly changed, and is only mentioned here for the sake of completeness:</p><pre style="font-size: 12px">private void ParentPageOrientationChanged(object sender, OrientationChangedEventArgs e) { SetVideoOrienta </body>