Memory usage is an important aspect, especially on mobile device. If you want to publish an app on the Windows Phone marketplace you must satisfy the Technical Certification Requirements: “5.2.5 Memory Consumption: An application must not exceed 90 MB of RAM usage, except on devices that have more than 256 MB of memory.”

In this post, I’m sharing a technique to track the memory usage of a WP7 app in real tile in every single page of the app. By adding only one line of code in your existing app, you’ll be able to display memory usage in all your pages (without any changes):

Download source code and example

How to integrate the component in your existing app?

1. import the MemoryWatcher class in your existing project
2. in the InitializePhoneApplication method, add a new line after the creation of the RootFrame:

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// Create the frame but don't set it as RootVisual yet; this allows the splash
// screen to remain active until the application is ready to render.
RootFrame = new PhoneApplicationFrame();
// Add the following line !
new MemoryWatcher(RootFrame) { IsDisplayed = true };

How it works?

During its initialization, the MemoryWatcher control will set an event handler to have a callback whenever the user navigates to a new page. When the new page is loaded, it checks if it can dynamically insert the MemoryWatcher control. This is done by checking the root UI element of the page and inserting the watcher control in it. Here is the full code of the MemoryWatcher class:

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using System;
using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Navigation;
using System.Windows.Threading;
 
using Microsoft.Phone.Controls;
using Microsoft.Phone.Info;
 
namespace MemoryWatcherDemo
{
    public class MemoryWatcher : ContentControl
    {
        private readonly DispatcherTimer timer;
        private readonly PhoneApplicationFrame frame;
        private const float ByteToMega = 1024 * 1024;
 
        public bool IsDisplayed { get; set; }
 
        public MemoryWatcher(PhoneApplicationFrame frame)
        {
            if (frame == null)
                throw new ArgumentNullException("frame");
 
            this.frame = frame;
            this.frame.Navigated += new NavigatedEventHandler(this.OnFrameNavigated);
            this.frame.Navigating += new NavigatingCancelEventHandler(this.OnFrameNavigating);
 
            this.timer = new DispatcherTimer { Interval = TimeSpan.FromMilliseconds(100) };
            this.timer.Tick += new EventHandler(this.OnTimerTick);
 
            // setup some basic properties to ensure the content will be visible
            this.Foreground = new SolidColorBrush(Colors.Red);
            this.VerticalContentAlignment = VerticalAlignment.Center;
            this.HorizontalContentAlignment = HorizontalAlignment.Center;
            this.Margin = new Thickness(0, -35, 0, 0);
        }
 
        private void OnFrameNavigated(object sender, NavigationEventArgs e)
        {
            if (!this.IsDisplayed)
                return;
 
            var page = this.frame.Content as PhoneApplicationPage;
            if (page != null)
            {
                Panel host = page.Content as Panel;
                if (host != null && !host.Children.Any(c => c is MemoryWatcher))
                {
                    this.timer.Start();
                    host.Children.Add(this);
                }
            }
        }
 
        private void OnFrameNavigating(object sender, NavigatingCancelEventArgs navigatingCancelEventArgs)
        {
            var page = this.frame.Content as PhoneApplicationPage;
            if (page != null)
            {
                Panel host = page.Content as Panel;
                if (host != null && host.Children.Contains(this))
                {
                    this.timer.Stop();
                    host.Children.Remove(this);
                }
            }
        }
 
        private void OnTimerTick(object sender, EventArgs e)
        {
            try
            {
                string currentMemory = (DeviceStatus.ApplicationCurrentMemoryUsage / ByteToMega).ToString("#.00");
                string peakMemory = (DeviceStatus.ApplicationPeakMemoryUsage / ByteToMega).ToString("#.00");
 
                this.Content = string.Format("Current: {0}MB Peak: {1}MB", currentMemory, peakMemory);
            }
            catch (Exception)
            {
                this.timer.Stop();
            }
        }
    }
}

Note:

• The MemoryWatcher is looking for a Panel type in order to add itself to the list of children in the page. You might want to modify and improve this portion in order to better fit your needs.
• The attached project targets Windows Phone 7.1, if you want to use the code in a 7.0 version, you should change the way the memory values are read (see this article for more details)

Enjoy the code and start tracking memory leaks

Download source code and example

Next Wednesday (November 9th), I’ll be at the Microsoft Days 11 as a member of the Ask The Expert team. I’ll be playing with the Samsung Slate I got at //BUILD/, discussing WPF, Silverlight, Windows Phone 7 and Windows 8.

Don’t hesitate to stop by and say hi if you’re coming to this event !

Here is the top 5 of MVVM frameworks supporting WPF, Silverlight and Windows Phone 7:

1. MVVM Light (61k downloads)
2. nRoute (19k downloads)
3. Caliburn Micro (18k downloads)
4. Simple MVVM toolkit (5k downloads)
5. Catel (5k downloads)

Windows Phone 7 SDK comes with a set of Task (in the Microsoft.Phone.Tasks namespace). A task can be launched from your application in order to perform some work. Currently available tasks are:

• Capture Camera (StartCameraTask)
• Choose Email Address (EmailAddressChooserTask)
• Compose Email (EmailComposeTask)
• Open Market Place (MarketplaceLauncher)
• Open Media Player (MediaPlayerLauncher)
• Make Phone Call (PhoneCallTask)
• Pick Phone Number (PhoneNumberChooserTask)
• Choose Photo (PhotoChooserTask)
• Save Email (SaveEmailAddressTask)
• Save Phone Number (SavePhoneNumberTask)
• Search (SearchTask)
• Compose SMS (SmsComposeTask)
• Browse Web (WebBrowserTask)

In order to launch a task from your application, all you need to do is to instantiate the associated type and call the Show() method.

Here is a sample code which launchs the StartCameraTask and then gets the capture images in order to use it in a standard Silverlight Image control:

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// launch the camera capture when the user touch the screen
this.MouseLeftButtonUp += (s, e) => new CameraCaptureTask().Show();
 
// this static event is raised when a task completes its job
ChooserListener.ChooserCompleted += (s, e) =>
{
    var taskEventArgs = (TaskEventArgs<PhotoResult>)e;
    var photoStream = taskEventArgs.Result.ChosenPhoto;
 
    var bitmapImage = new BitmapImage();
    bitmapImage.SetSource(photoStream);
 
    this.image.Source = bitmapImage;
};

The image is just a standard Silverlight Image control:

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<Image x:Name="image"/>

The emulator while the task is running:

The captured image (shown once the task has completed):

If you haven’t download the tool already, go ahead and grab them ! Everything is available for free in a single download at http://developer.windowsphone.com/windows-phone-7-series/.

Hope this helps

Note: even though the StartCameraTask is now working, this is not yet the case for all the tasks…

You’ll need not more than a couple of minutes to download and install all the tools needed to create your first Windows Phone application using Blend.

Here is a tour in images:

Welcome in Blend 4

Discovering new projects templates in the Welcome dialog:

It must be quite familiar to you if you’re working with WPF or Silverlight

Choosing a target

Launching the app in the emulator

App.xaml file has all the resources for the Windows Phone theme

Let’s go now and play with the tools

The first keynote of Mix10 is just over and the biggest announcement I was waiting for occured: Windows Phone 7 series development tools are NOW available for FREE.

Grab the tools right now ! You’ll need:

• Expression Blend 4 Beta
• Windows Phone Developer Tools
• Expression Blend Add-in for Windows Phone
• Expression Blend SDK for Windows Phone

If you want more details about Blend4, you can check out Christian Schormann’s overview. A new website is now live for all Windows Phone 7 series related development information at http://developer.windowsphone.com/

Another announcements is the availability of Silverlight 4 RC and support for VS2010 RC:

• Silverlight 4 Tools for Visual Studio 2010 (this installs Silverlight developer runtime, SDK, tools, and WCF RIA Services).
• Silverlight Toolkit March 2010 Release
• WCF RIA Services Toolkit
• Expression Blend 4 beta
• BREAKING CHANGES DOCUMENTATION
• Windows Phone Developer tools

For more information about Silverlight 4 RC, you can check out the blog post of Tim Heuer.

I can’t wait to play with all this new stuff. It’s very impressive to see the work done around Windows Phone 7 series. WPF and Silverlight developers just became Windows Phone developer today, and I think this is great !

I’ll give more feedback as soon as the tools will be installed

To make the long story short :

• Windows Mobile 7 was presented during last WMC (Word Mobile Congress) under the name “Windows Phone 7 series”
• Microsoft demonstrated the new UI experience coming with this new version
• Microsoft confirmed that Silverlight and XNA will be the technologies available to develop on the Windows Phone
• Microsoft shows off single game running on Windows, Windows Phone and Xbox

I’m sure you realize that we are going to a very capable and powerful mobile platform here:

• all existing .Net and Silverlight developers are going to be able to write apps for the Windows Phone (this is HUGE)
• we are going to finally have the 3 screens version of Microsoft: develop once and then run on your mobile, your PC and your TV (XBox)

Mix10 website now contains the name and the description of the sessions which are dedicated to the Windows Phone 7 series:

• Designing and Developing for the Rich Mobile Web
• Building a High Performance 3D Game for Windows Phone
• Building Windows Phone Games
• Changing our Game – an Introduction to Windows Phone 7 Series
• An Introduction to Developing Applications for Microsoft Silverlight
• Windows Phone UI and Design Language
• Overview of the Windows Phone 7 Series Application Platform
• Building Windows Phone Applications with Silverlight, Part 1
• Building Windows Phone Applications with Silverlight, Part 2
• Unit Testing Silverlight and Windows Phone 7 Applications
• Silverlight Performance on Windows Phone
• Distributing and Monetizing Windows Phone Applications and Games
• Development and Debugging Tools for Building XNA Games for Windows Phone
• Windows Phone Application Platform Architecture

If you’re using Twitter, make sure to watch the #wp7 hashtag. It make not any doubt the next week is going to be very informative about Windows Phone 7 series.So stay tuned !