UPDATE: It is working, but you need to give your app some special permissions. Description is well hidden in MSDN documentation: <rescap:Capability Name=„appointmentsSystem“/>
UWP (Universal windows platform) is a great idea!
Developers can create apps that target UWP an these apps are able to run on all windows 10 devices that support UWP like Windows 10, Windows Mobile 10, Rasperi Pi, XBox, Hololens…maybe some time 😉
Porting existing apps based on Silverlight or WinRT (all existing windows phone and windows store apps) to UWP is not that hard – thats what MS says – so that’s what I want to do with my apps.
Since Week View it’s my most downloaded app, and I want my users to be able to use it on all their windows devices, I am currently trying to port Week View to an UWP app.
In fact it will be a complete rewrite. 🙂
While creating apps I learned a lot of things and starting from scratch allows me to build a new „base infrastructure“ to make the app more flexible and in the future adding new features should be easier to do. I still want to provide it as free update for existing users.
Additionally I want to use new features like „compiled binding“ which should increase the general responsibility and performance of the app.
The plan: Week View should run on Windows 10, Windows Mobile 10 and all other devices that support UWP.
While porting Week View to UWP I discovered an unexpected behaviour: Creating appointments is not working. MS provides a method that developers can call to create an appointment (similar to windows phone 8.x) but when this method is called, the app crashes!
I consider this as a critical bug and can’t believe nobody at MS recogniced this problem but it seems other developer have this problem too, please see: https://social.msdn.microsoft.com/Forums/windowsserver/en-US/0d6e0b0f-dc4a-4f52-a52e-f25b78543258/uwp-are-calendars-still-readonly-in-windows-10?forum=wpdevelop
In fact this bug is a „showstopper“ and currently developers cannot port their calendar apps to UWP since the most basic feature „creating appointments“ is not working.
I still hope all this will be resoved by MS and will do some more „research“ myself. The windows 10/windows phone 10 developer preview included calendar is really bad (in my opinion) but at least it CAN create appointments so there must be a way to do this.
This eithrr means it uses a different programing interface which would be very strange since MS always said that the exiting apps are created using the same programing interface as provided for developers.
Another option is that the built in calendar uses permissions that are not available for developers which would be very strange too.
I hope MS support will answer the support thread mentioned above an am very curious what the answer will be.
Update: I created a separate thread in the windows phone developers forum for this issue https://social.msdn.microsoft.com/Forums/windowsapps/en-US/cd37cebe-c1bc-4138-8e91-e6b5a8907fb6/creating-an-appointment-in-a-uwp-app-crashes-the-app?forum=wpdevelop