Xamarin Forms 5 - UWP Upgrade Issues

Question

Xamarin Forms 5 - UWP Upgrade Issues

Konstantinos Koumpanakis 1

Hello everyone,

Our team is in the process of migrating from Xamarin.Forms 4.4.0.991864 to the latest stable 5.0.0.2012.
Though the Android App runs without any problems with XF 5, that's not the case for the UWP App .
I followed the instructions for upgrading to XF 5 https://learn.microsoft.com/en-us/xamarin/xamarin-forms/troubleshooting/questions/forms5-migration that state that for the UWP, an upgrade to the target version 10.0.18362.0 is enough to make it work.
After doing that and installing Xamarin.Forms 5.0.0.2012 I encounter 2 major issues.

Whenever I call DIsplayAlert() the UWP app hangs. The page becomes transparent and I cannot interact in any way. I made sure I called DisplayAlert() on the UI thread.
When I try to navigate from our main page to another one, I encounter the exception 'Cannot find a Resource with the Name/Key SmallScrollThumbScale [Line: 16724 Position: 86]' that is type of Windows.UI.Xaml.UnhandledExceptionEventArgs and thrown by App.xaml of the UWP App.

My initial question is: Am I missing any mandatory steps for setting up Xamarin Forms 5 correctly on UWP? Are there any steps like upgrading a certain nugget package or migrating any code that I am missing? Any guidance would be really helpful.

Thank you.

Kyle Wang 5,531 Reputation points Microsoft External Staff

2021-06-09T05:37:11.347+00:00

@Konstantinos Koumpanakis In my test, I create a project with Xamarin 4 and then update it to XF5. The "DIsplayAlert" also works fine. So to reproduce the issue, could you provide a minimal, reproduible "Xamarin.Forms 4" example via OneDrive or Github?
Konstantinos Koumpanakis 1 Reputation point

2021-06-09T11:12:27.357+00:00

@Kyle Wang Thank you very much for your quick reply. I indeed confirm that my assumption that something is wrong with the DisplayAlert is invalid as I tested it with another XF5 project and it works.
My main concern is if I'm missing any necessary steps to upgrade a UWP app to XF5 that are not mentioned in the official guide https://learn.microsoft.com/en-us/xamarin/xamarin-forms/troubleshooting/questions/forms5-migration ?
Was changing the target platform version of your UWP app enough for you in order to upgrade from XF4 to XF5?

Thanks in advance.
Kyle Wang 5,531 Reputation points Microsoft External Staff

2021-06-10T02:11:30.877+00:00

@Konstantinos Koumpanakis So far, according to the documentation you only need to set the target platform version. The only thing to note is to update the XF in each project to the same version.