Failure to load in unpackaged MAUI apps

[SittenSpynne]

I'm trying to create an unpackaged MAUI app for a certain deployment scenario. Our application uses MonkeyCache. When I start the application, it fails with an InvalidOperationException. The call stack implies it's failing when it uses Windows.Storage.ApplicationData.get_Current(), which I presume requires MSIX packaging to work properly.

I validated this by doing as follows:

1. Create a new MAUI application using the VS templates.
2. Edit the .csproj to produce an unpackaged app by adding <WindowsPackageType>None</WindowsPackageType>.
3. Update the launchSettings.json file to not use package actions by changing command to "Project".
4. Add a bit of code to MainPage.xaml.cs:

        protected override void OnAppearing()
        {
            base.OnAppearing();

            try
            {
                MonkeyCache.SQLite.Barrel.ApplicationId = "MauiApp1";

                var currentBarrel = Barrel.Current;
                
            }
            catch (Exception ex)
            {
                DisplayAlert("Error", ex.Message, "OK");
                throw;
            }
        }

The call stack:

System.InvalidOperationException: Operation is not valid due to the current state of the object.
   at WinRT.ExceptionHelpers.<ThrowExceptionForHR>g__Throw|39_0(Int32 hr)
   at WinRT.ExceptionHelpers.ThrowExceptionForHR(Int32 hr)
   at ABI.Windows.Storage.IApplicationDataStaticsMethods.get_Current(IObjectReference _obj)
   at Windows.Storage.ApplicationData.get_Current()
   at MonkeyCache.BarrelUtils.GetBasePath(String applicationId)
   at MonkeyCache.SQLite.MonkeyBarrel.<>c.<.cctor>b__32_0()
   at System.Lazy`1.ViaFactory(LazyThreadSafetyMode mode)
   at System.Lazy`1.ExecutionAndPublication(LazyHelper executionAndPublication, Boolean useDefaultConstructor)
   at System.Lazy`1.CreateValue()
   at MonkeyCache.SQLite.MonkeyBarrel..ctor(String cacheDirectory)
   at MonkeyCache.SQLite.MonkeyBarrel.get_Current()
   at [my redacted call site]

I'm looking at the code and the most inelegant fix would be a try..catch in the #if WINDOWS section. If it used the Environment.GetFolderPath() method as a fallback that would work here. I'm not sure if there's a way this code could tell if it's been packaged or not so that might be the solution?

[jamesmontemagno]

work around is to set your own path