XAML Wonderland

I heard this nugget from Derek Lakin on Twitter: 

Press and Hold is  the discovery combination that every Windows phone 7 user should know.

We were having a conversation around the Windows Phone 7 on-screen keyboard.  In order to keep the keyboard compact Microsoft stows alternate character beneath common keys.  Take punctuation for example.  On the default alpha keyboard there are two punctuation keys (period and comma).  If you press and hold the period key another set of keys appears.

This also works for accented (diacritical) characters.

Accented characters on the Keyboard

===========================

Huge library of online Silverlight videos.  Why not check it out?

All  Windows Phone 7 applications undergo a security analysis when uploaded to the Windows Phone Marketplace.   The analyzer checks to see what services your app requires and verifies that you have requested those services in the Application Manifest.

Windows Phone provides a capabilities-driven security model where a user must opt-in to certain functionality within the application. For certain scenarios, Windows Phone APIs invoked by applications may require specific security permissions or user disclosure when run. By default, when you create a Windows Phone project, an application manifest file is auto-generated that includes a list of the all the phone capabilities supported by Windows Phone. The Windows Phone operating system will grant security permissions to the application according to the capabilities listed in that manifest file

The Phone SDK includes the Windows Phone Capability Detection Tool to help determine which capabilities to include in the manifest before submitting your application to Microsoft.

Be wary of third party DLLs

Adding references to other DLLs can increase your security footprint. Any access requested in your referenced assemblies is considered part of your application capabilities too. I’ve been working with the AdControl in the Microsoft.advertising.Mobile.UI.dll for a upcoming project.   I noticed that it adds the following capabilities to the required list.

• ID_CAP_PHONEDIALER
• ID_CAP_NETWORKING
• ID_CAP_WEBBROWSERCOMPONENT
• ID_CAP_IDENTITY_USER

I’m working on a Windows Phone 7 application that is using the Microsoft ad network.  Microsoft simplifies the process by providing an AdControl control in the Advertising SDK.

To add the control to your XAML is easy.

    <my1:AdControl Grid.Row=’0′
                  ApplicationId=‘ba766 etc.’
                  AdUnitId=’100xxxxxxx’
                  Width=’480′
                  Height=’80′
                  HorizontalAlignment=‘Center’
                  VerticalAlignment=‘Center’ />

Next, you need to configure some ad campaigns on the Microsoft ad  center and add the correct ApplicationId and AdUnitId to your XAML. Now, when the AdControl is shown on the page, you should see it populated with data.

Failure

In our app everything worked correctly for a day or two.  Eventually we noticed that we did not see the ad when testing on the device.   After wasting hours of time  investigating the problem the answer emerged.

You must not disable the ID_CAP_NETWORKING capability in the WMAppManifest.xml

  <Capabilities>

      <Capability Name="ID_CAP_IDENTITY_DEVICE" />
      <Capability Name="ID_CAP_IDENTITY_USER" />
      <Capability Name="ID_CAP_NETWORKING"/>

   </Capabilities>

Failing to set this capability causes the AdControl to fail when connecting to the ad network.  This, in turn, causes the AdControl to collapse in the UI. So no ads.

In hindsight, this makes sense, as the control needs to contact the server.  But this isn’t documented anywhere that I have found.

I’m one of the lucky few to have access to a developer device.  I’m currently using the Samsung Taylor and it is really a nice phone.  I’m looking forward to seeing the production phones, which have a faster processers, more RAM etc.

Having the device is invaluable for debugging and testing.  For example one of the certification requirements is that you app cannot use more the 90MB of memory.  Running on the hardware I stumbled across an interesting limitation while developing a new app.  On the device, going over the memory limit causes the phone to raise a NavigationFailed event when calling NavigationService.Navigate.   See this thread on the phone forums for more information.  I spent too much time debugging the navigation problem, when what I really needed to look at was the massive amount of memory consumed by the Panorama control.  Lesson learned:  pay more attention to the performance counters at every stage of your application cycle.

Built-in counters

You may already know about the counters included in the phone API.  In fact, they are hard to miss in the RTM release.  They are included in the default template, and setup to run when ever you attach a debugger to your phone application. Jeff Wilcox has a lengthy blog post if you want to learn more.

Memory Counters

Unfortunately these counter do not include an important metric.  They are missing memory usage counters.  Not to worry however. Garry McGlennon has released a counter which shows these important stats.

I’ve added it to my application and plan on using it during all future development.

Want to watch some Silverlight online training?

You can customize the image shown in your Windows Phone 7 Tile.  All you need to do is change the BackgroundImageURI value in the WMAppManifest.xml file.

  <Tokens>
      <PrimaryToken TokenID="MyAppToken" TaskName="_default">
        <TemplateType5>
          <BackgroundImageURI IsRelative="true" 

                              IsResource="false">

                              /Images/Coins/tileImage.png</BackgroundImageURI>

You can also change this value in the Visual Studio 2010 Property page.

Figure 1:  Change Background Image in Property page.

Visual Studio 2010 Bug

Unfortunately there is a bug in Visual Studio.  If you choose the image using the property page the full path the the image to the image is not added to the WMAppManifest.xml.

<BackgroundImageURI IsRelative="true" 

                    IsResource="false">

                 tileImage.png</BackgroundImageURI>

Without the complete path the image won’t show in the applications Tile.

It’s easy to embed information inside your assembly. Just add it to the assemblyInfo.cs/assemblyInfo.vb  file or use the Visual Studio properties window.

Reading the AssemblyInfo data

When you want to read this information from a Silverlight/WindowsPhone assembly you can call on the Assembly class to get the desired data.

You can use the GetExecutingAssembly method and the AssemblyName class to find this information.

var nameHelper = new AssemblyName(Assembly.GetExecutingAssembly().FullName);

var version = nameHelper.Version;
var full = nameHelper.FullName;
var name = nameHelper.Name;

[Edit]

Why not use a call to Assembly.GetExecutingAssembly().GetName()?  In the Silverlight API that call throws an exception. 

Windows Phone 7, like most modern touch screen phones, has an on screen keyboard.  It’s known as the Software Input panel (SIP) and it is a virtual keyboard that appears when a text-input control such as a TextBox gets the input focus.

There are 50+ keyboards configurations available.  Figure 1 shows the default keyboard layout.

Figure 1: Default SIP

How to input accented (diacritical ) characters

It is simple to input accented and alternate letters if you know the secret.  Press and hold a letter on the SIP to see the available list of alternate characters.

Here are some sample screenshots.