BasemapGallery loading demo data in production release

[espenrl]

Hi, I have a hard time initializing BasemapGallery.AvailableBasemaps with a custom list of basemaps. The shown gallery is overridden by the loading of what seems to be demo data. Except for a sample app, why would one want this behavior?

PS: Not using a portal

arcgis-maps-sdk-dotnet-toolkit/src/Toolkit/Toolkit.Maui/BasemapGallery/BasemapGallery.cs

Lines 37 to 45 in 5a3260c

	public BasemapGallery()
	{
	_controller = new BasemapGalleryController();
	_controller.PropertyChanged += HandleControllerPropertyChanged;
	ListItemTemplate = DefaultListDataTemplate;
	GridItemTemplate = DefaultGridDataTemplate;
	ControlTemplate = DefaultControlTemplate;
	_ = _controller.LoadFromDefaultPortal();
	}

[dotMorten]

The shown gallery is overridden by the loading of what seems to be demo data

Could you clarify what you mean by that? Any chance you could provide a small reproducer that demonstrates the issue?

[espenrl]

I can see I was a bit short in my description. I'll explain myself more clearly.

If I add this xaml

<toolkit:BasemapGallery />

then I get a list of maps

I would expect to get an empty basemap gallery, I expect to get nothing at all. That is what I think of as "demo basemaps". For me it is a bit unusual that a UI control loads default data.

Then I try this expecting to stop loading the "demo basemaps"

<toolkit:BasemapGallery Portal="{x:Null}" />

But it still continues loading.

Next up is

<toolkit:BasemapGallery Portal="{x:Null}"
                        AvailableBasemaps="{Binding Basemaps}" />

public MapPageViewModel()
{
    LoadBasemapGallery();
}

private async void LoadBasemapGallery()
{
    var aTask = BasemapGalleryItem.CreateAsync(new Basemap(new ArcGISTiledLayer(new Uri(Constants.GeodataServiceUri.Bilder))));
    var bTask = BasemapGalleryItem.CreateAsync(new Basemap(new ArcGISTiledLayer(new Uri(Constants.GeodataServiceUri.VectorNordenBasisTerreng))));
    var cTask = BasemapGalleryItem.CreateAsync(new Basemap(new ArcGISTiledLayer(new Uri(Constants.GeodataServiceUri.VectorNordenGråtoneTerreng))));

    await Task.WhenAll(aTask, bTask, cTask);

    Basemaps.Add(aTask.Result);
    Basemaps.Add(bTask.Result);
    Basemaps.Add(cTask.Result);
}

public ObservableCollection<BasemapGalleryItem> Basemaps { get; } = new();

But it still continues to load the "demo basemaps" and I can't get it to show my custom basemaps definition.

At this point I looked up the source code

arcgis-maps-sdk-dotnet-toolkit/src/Toolkit/Toolkit.Maui/BasemapGallery/BasemapGallery.cs

Lines 37 to 45 in 5a3260c

	public BasemapGallery()
	{
	_controller = new BasemapGalleryController();
	_controller.PropertyChanged += HandleControllerPropertyChanged;
	ListItemTemplate = DefaultListDataTemplate;
	GridItemTemplate = DefaultGridDataTemplate;
	ControlTemplate = DefaultControlTemplate;
	_ = _controller.LoadFromDefaultPortal();
	}

..and discovered that the loading of initial "demo basemaps" are triggered from the constructor regardless of anything else. For apps that don't use this initial setup of basemaps I think that is a bit unfortunate. It also leads to many ArcGISWebException because of missing ChallengeHandler setup, thus slowing down app startup.