I am trying to switch over a WPF application to use custom vector basemaps. My app has several maps that show up in different spots, which are implemented as separate view/viewmodel instances (with no shared data, unfortunately).
If I initialize like this:
_map = new Map(BasemapType.TopographicVector, 0, 0, 0);
It works as expected. All the maps all show up fine.
If instead I initialize like this:
var arcGisOnline = await ArcGISPortal.CreateAsync(new Uri("https://www.arcgis.com"));
var layerPortalItem = await PortalItem.CreateAsync(arcGisOnline, "88f339245400469e88d784524ae80fca");
var customVectorTileLayer = new ArcGISVectorTiledLayer(layerPortalItem);
_map = new Map(new Basemap(customVectorTileLayer));
The map shows up in the first view correctly. In the other views it's blank (white). No error messages are emitted on the console. Bottom right of the canvas says "Powered by Esri", bottom left says nothing. The working instance has a dark gray background (with the map on top), says "Licensed for Developer Use Only", has "Esri, FAO, NOAA, NRCan" in the lower left and "Powered by Esri" in the lower right.