public IReadOnlyList<SectionDefinition> GetSelectedSections()

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)

//var voxelLayer = ... ;
//Must be on the QueuedTask.Run()

var section = MapView.Active?.GetSelectedSections()?.FirstOrDefault();
if (section != null)
{

}

//var voxelLayer = ... ;
//Must be on the QueuedTask.Run()

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

      //var voxelLayer = ... ;
      //Must be on the QueuedTask.Run()

      if (voxelLayer.Visualization != VoxelVisualization.Surface)
          voxelLayer.SetVisualization(VoxelVisualization.Surface);
      voxelLayer.SetSectionContainerExpanded(true);
      voxelLayer.SetLockedSectionContainerExpanded(true);
      voxelLayer.SetLockedSectionContainerVisibility(true);

      //Use the SelectedVariableProfile to get the sections
      //via its associated volume
      var volume = voxelLayer.SelectedVariableProfile.Volume;

      //get the selected section
      var section = MapView.Active.GetSelectedSections().FirstOrDefault();
      if (section == null)
{
          //At 2.x - section = voxelLayer.GetSections().FirstOrDefault();
          section = volume.GetSections().FirstOrDefault();
      }

      if (section == null)
          return;

      //Lock the section (Creates a locked section, deletes
      //the section)
      //if (voxelLayer.CanLockSection(section))
      //    voxelLayer.LockSection(section);
      if (volume.CanLockSection(section))
          volume.LockSection(section);