public void SetUseSymbolLayerDrawing( 
   bool useSLD
)

QueuedTask.Run(() =>
{
  //A layer may have SLD added but is not using it
  //HasSymbolLayerDrawingAdded returns a tuple - to check
  //the layer has SLD (not its parent) check addedOnLayer
  if (featLayer.HasSymbolLayerDrawingAdded().addedOnLayer)
  {
    //the layer has SLD but is the layer currently using it?
    //GetUseSymbolLayerDrawing returns a tuple - useOnLayer for 
    //the layer (and useOnParent for the parent layer)
    if (!featLayer.GetUseSymbolLayerDrawing().useOnLayer)
    {
      //enable it
      featLayer.SetUseSymbolLayerDrawing(true);
    }
  }

  //Enable/Disable SLD on a layer parent
  if (featLayer.HasSymbolLayerDrawingAdded().addedOnParent)
  {
    //check parent...this can be recursive
    var parent = GetParentLayerWithSLD(featLayer.Parent as GroupLayer);
    if (parent.GetUseSymbolLayerDrawing().useOnLayer)
      parent.SetUseSymbolLayerDrawing(true);
  }
  /*
   * 
   //Recursively get the parent with SLD
   public GroupLayer GetParentLayerWithSLD(GroupLayer groupLayer) 
   {
     if (groupLayer == null)
       return null;
     //Must be on QueuedTask
     var sld_added = groupLayer.HasSymbolLayerDrawingAdded();
     if (sld_added.addedOnLayer)
       return groupLayer;
     else if (sld_added.addedOnParent)
       return GetParentLayerWithSLD(groupLayer.Parent as GroupLayer);
     return null;
   }
  */
});