WinRT License API, Silverlight 8.1 apps and sideload detection #wpdev

Since early 2011, I have been using the method described here.
Recently I have been upgrading all my apps to target Windows Phone 8.1 API. Most of previous API is still accessible in WP 8.1 SL8.1 apps. However a great deal more is available under WinRT API.

With my Alarm Clock app, I have started using WinRT API to pin and update Tiles. I have used WinRT API for background tasks as I can run them more frequently and I can detect Timezone change. I have added IAP to the app.
The app however is available in 2 flavours Free (with ads and restrictions) and Paid. So far I have only been updating the paid app. Of course I use sideload detection for Paid app however while considering update of Free version, I decided to use CurrenApp to execute License check and potentially offer to convert Free users in-place as opposed to getting them to buy another app!!

In good old SL API, I would have used

var license = new Microsoft.Phone.Marketplace.LicenseInformation();
IsTrial = license.IsTrial();

With WinRT that becomes

IsTrial = CurrentApp.LicenseInformation.IsTrial;

While developing and deploying if you observe the behaviour, the IsTrial never returns false. You cannot test Trial scenario without explicit pre-processor directives!
Of course CurrentAppSimulator is only available for WinRT app and not SL8.1 apps. The same behaviour would be exposed by the sideloaded apps. Not downloaded from store equates to full version. Like in good old days, WMAppPRHeader.xml is still attached after certification. So lets modify the code

try
{
   XDocument doc = XDocument.Load("WMAppPRHeader.xml");
 
   IsTrial = CurrentApp.LicenseInformation.IsTrial;
}
catch
{
   IsTrial = true;
}

You treat all apps without WMAppPRHeader.xml as trial. Job done!
Note that IAP are not affected. If you had TestIAP, it is not active by default.

CurrentApp.LicenseInformation.ProductLicenses["TestIAP"].IsActive;

Happy coding!

5 thoughts on “WinRT License API, Silverlight 8.1 apps and sideload detection #wpdev

  1. Love your app, I’ve got the paid version, but after the last update it does not work right. When I got the Cyan update to my Lumia 820 I moved all movable programs to the sd-memory, but after the last update I just could not start my Alarm Clock. So I’ve moved it back to mobile memory, and now it starts, but it all of a sudden shuts down again.

    Hope you can fix this. This app is the only thing that manage to get me up in the morning:-)

    • I am not sure what went wrong with the last update!! sadly my laptop crashed the very day and I have been scrambling to get it working. I have submitted a fix to store. lets hope it gets through soon

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