Unable to display dialog using IDialogService (.NET 8/Prism 9.0.271-pre)

[MartinRobins]

Having had it confirmed that the latest build (9.0.271-pre) supports IDialogService in MAUI, I am still struggling to actually make this work. As @dansiegel has already pointed out to me, the documentation is out of date (it says that IDialogService is not supported in MAUI and also defines IDialogService differently to the XF examples) so I have been trying to find my own way around it but am struggling to find any working examples.

The attached project reproduces my problem. If you click on the "Dialog" button on the main page (or the flyout page), you see the mask for 5 seconds and then it clears (note: this is deliberate as the dialog is closed automatically from the viewmodel - it will be used to show a task status) but you do not see any of the content defined in the SynchronisationDialog.xaml.

Any help identifying what I have missed will be greatly appreciated.

(note: Please ignore the use of the TaskDialogViewModelBase; this is a hangover from a previous example and does not actually belong to the problem as the "OnNavigatedTo" is not used in IDialogService as far as I can see).

Thanks.

PrismIssue.zip

[MartinRobins]

New information...

If I specify either or both of the RelativeHeightRequest/RelativeWidthRequest in th Xaml of the view I am using as the dialog...

<Frame x:Class="PrismIssue.Views.SynchronisationDialog"
       ...
       xmlns:prism="http://prismlibrary.com"
       ...
       prism:DialogLayout.RelativeWidthRequest="0.9"
       prism:DialogLayout.RelativeHeightRequest="0.9">

       ...

</Frame>

The dialog does not show. If however I remove these attributes and set the dialog size manually (HeightRequest/WidthRequest), the dialog shows and operates correctly.

Gets me by for now to simply remove the attributes, but I still do not understand why it is that they do not work. Is this me, is this unfinished functionality in the preview build I am using, or is this a bug?

[MartinRobins]

But that now gives me a new error if I click the back button 😒😒

[mono-rt] [ERROR] FATAL UNHANDLED EXCEPTION: System.NullReferenceException: Object reference not set to an instance of an object.
[mono-rt]    at Prism.Ioc.IContainerProviderExtensions.Resolve[INavigationService](IContainerProvider provider) in /_/src/Prism.Container.Abstractions/IContainerProviderExtensions.cs:line 16
[mono-rt]    at Prism.Navigation.Xaml.Navigation.GetNavigationService(Page page) in D:\a\Prism\Prism\src\Maui\Prism.Maui\Navigation\Xaml\Navigation.cs:line 117
[mono-rt]    at Prism.Navigation.PrismWindow.PrismWindow_ModalPopping(Object sender, ModalPoppingEventArgs e) in D:\a\Prism\Prism\src\Maui\Prism.Maui\Navigation\PrismWindow.cs:line 82
[mono-rt]    at System.Threading.Tasks.Task.<>c.<ThrowAsync>b__128_0(Object state)
[mono-rt]    at Android.App.SyncContext.<>c__DisplayClass2_0.<Post>b__0() in /Users/runner/work/1/s/xamarin-android/src/Mono.Android/Android.App/SyncContext.cs:line 36
[mono-rt]    at Java.Lang.Thread.RunnableImplementor.Run() in /Users/runner/work/1/s/xamarin-android/src/Mono.Android/Java.Lang/Thread.cs:line 36
[mono-rt]    at Java.Lang.IRunnableInvoker.n_Run(IntPtr jnienv, IntPtr native__this) in /Users/runner/work/1/s/xamarin-android/src/Mono.Android/obj/Release/net8.0/android-34/mcw/Java.Lang.IRunnable.cs:line 84
[mono-rt]    at Android.Runtime.JNINativeWrapper.Wrap_JniMarshal_PP_V(_JniMarshal_PP_V callback, IntPtr jnienv, IntPtr klazz) in /Users/runner/work/1/s/xamarin-android/src/Mono.Android/Android.Runtime/JNINativeWrapper.g.cs:line 26