public IReadOnlyList<SliceDefinition> GetSelectedSlices()

var surfaces = MapView.Active.GetSelectedIsosurfaces();
//set selected w/ MapView.Active.SelectVoxelIsosurface(isoSurface)
var slices = MapView.Active.GetSelectedSlices();
//set selected w/ MapView.Active.SelectVoxelSlice(slice)
var sections = MapView.Active.GetSelectedSections();
//set selected w/ MapView.Active.SelectVoxelSection(section)
var locked_sections = MapView.Active.GetSelectedLockedSections();
//set selected w/ MapView.Active.SelectVoxelLockedSection(locked_section)

//Must be on the QueuedTask.Run()

VoxelLayer voxelLayer = null;
var slice = MapView.Active?.GetSelectedSlices()?.FirstOrDefault();
if (slice != null)
{
    voxelLayer = slice.Layer;
    //TODO - use the layer
}