Blog

The latest CTP release of Windows Phone 7 introduces a new managed library which exposes events you can monitor to catch changes in state in your application. The assembly is Microsoft.Phone.Execution.dll. This contains a WindowsPhoneEvents class which exposes two static methods – Pause and Resume. You can handle these events to detect when your application is dismissed and reactivated. This allows you to stop unnecessary processing and be a good citizen. I put together a simple example which shows how to pause a background thread based on these events and you can see the results by running it on the Emulator and switching to the home screen (Windows button) and returning to your application (Back button).

The sample uses a ManualResetEvent to block the background thread to avoid it consuming processor cycles while the app is paused.

Also in this assembly is the StreamPersister class. Unfortunately there is no documentation for this at the moment but an instance is passed in the Pause and Resume eventargs which will presumably allow you to safely persist state data which you can then load when your app is resumed. Hopefully there will be some official documentation on this to complete the picture.

Jamie Rodriguez has a post on the new capabilities security model in Windows Phone 7 which is introduced in the latest CTP release:-

http://blogs.msdn.com/jaimer/archive/2010/04/30/windows-phone-capabilities-security-model.aspx

It is interesting to read how this will be handled at runtime, here are the key facts:-

• If you try to use a feature and you didn’t specify the capability you’ll get an UnauthorizedAccessException when you first call that feature
• There is no API to check if you have been granted a specific capability
• The disclosure to the user will vary depending on the capability and marketplace – Either listed on the Marketplace page, a user prompt at purchase or a user prompt when the capability is about to be accessed.
• A new project created in the latest CTP will request all of the currently documented capabilities (you can remove those you don’t need later)
• There are other capabilities specific to OEMs and operators which are not documented
• The table of example features lists a few items yet to be shipped in the developer tools giving an interesting insight into what is still to come – Microsoft.Devices.Radio and Microsoft.Devices.MediaHistory

If you haven’t already heard there is a new release of the Windows Phone 7 Developer Tools available which is compatible with the RTM release of Visual Studio. Before you install you need to uninstall the previous version and this is where you might have problems. See this tool for cleaning up your machine:-

http://blogs.msdn.com/astebner/pages/9544320.aspx

Okay, now you’ve safely removed the old bits you can download the new installer from here:-

http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=cabcd5ed-7dfc-4731-9d7e-3220603cad14

Read the release notes:-

release notes

In particular there is a breaking change if you open existing projects – the WMAppManifest.xml requires some extra items to describe the application’s capabilities. There is also an issue with including Authenticode signed dlls (this includes official Microsoft libraries), you can read more about it here:-

http://timheuer.com/blog/archive/2010/04/29/windows-phone-tools-update-april-2010-silverlight-xna.aspx

Check out an overview of what is new in this release:-

What’s New in Windows Phone 7 CTP Refresh

Finally to end on a quick tip – Assuming you install on a machine without Visual Studio 2010 the “Visual Studio 2010 Express for Windows Phone” displays a simpler user interface than its big brother. You can quickly enable extra goodness by going to Tools > Settings > Expert Settings. This enables more menu and toolbar options and is definitely worthwhile if you are already familiar with Visual Studio.

If you have read the UI Guidelines for Windows Phone 7 (If you haven’t, get it now) you notice that in the discussion of the ApplicationBar it states that a maximum of four icons can be added. I noticed inadvertently that if you add five icons in your XAML your app will compile and run but only the first four are shown. If you add a sixth icon the designer will present you with an error.

It appears that this is a bug in the current CTP release and the control should support only adding four items. It previously supported five but this was reduced based on user feedback, obviously the validation in the current CTP is not strict enough but I expect this will be fixed in the next release.

Microsoft announced a pair of new phone devices which will be manufactured by Sharp and branded KIN. These are not part of the Windows Phone 7 platform but are still (perhaps confusingly) called Windows Phone. KIN uses a lot of the same underlying technology as Windows Mobile has in the past and Windows Phone will do, however the device is sharply focussed on social networking and the whole user experience revolves around this. The platform has built in support for Facebook, Twitter and MySpace along with the accompanying KIN Studio online service. KIN Studio is a web portal which aggregates everything you create on the phone up in the cloud. It has some cool visualisation of this content too including a timeline view of everything you’ve done. Think of it as a kind of MyPhone on steroids…

The user experience uses some of the same principles as the Metro user interface visible in Windows Phone 7 however one thing that is instantly noticeable is there is a lot less dead space. Where Windows Phone 7 uses large fonts and generous spacing in a “less is more” approach the KIN user interface packs highly graphical elements closely together. It has been described as a magazine style and certainly tries to catch your eye with everything which is going on in your social networks. Both platforms use a minimal colour scheme – from the flash based demo on the website you can choose one of four highlight colours but these are different to the colours used on the “big brother” Windows Phone 7.

I’m looking forward to seeing the real device, and I hope that some of these innovations (particularly KIN Studio) make it into Windows Phone 7 too! I’m also wondering if there will be any development story for these devices as there is nothing mentioned on the official website or press releases…

Microsoft have announced via Twitter that they have officially dropped the epic fail “Series” from the product name. Many have been referring to it as “Windows Phone 7” or “WP7” already and the “Series” was the latest in a series (sorry) of Microsoft adding redundant words to product names to unnecessarily confuse the public…