Layer file's labelling properties not importing

KisakyeM

I am importing symbology from a layer as below. After updating the symbology, I update the label expression  to use the label field in the current data. Once I turn on the labels however, the labels now have default properties; the label design from the imported layer is lost.  Font size and style are off and the halo is removed. How can I maintain the layer file's labelling properties with my new data?

 await QueuedTask.Run(() =>
            {
                var lyrDoc = new LayerDocument(LayerFilePath);
                var cimLyrDoc = lyrDoc.GetCIMLayerDocument();
                var rendFromLyrFile = ((CIMFeatureLayer)cimLyrDoc.LayerDefinitions[0]).Renderer as CIMUniqueValueRenderer;
                rendFromLyrFile.Fields= new string[] { "SiteDesc" };
                facLayer.SetRenderer(rendFromLyrFile);
            });
            //update the labels
            await QueuedTask.Run(() =>
            {    
                var def = facLayer.GetDefinition() as CIMFeatureLayer;
                var listLabelClasses = def.LabelClasses.ToList();
                var theLabelClass = listLabelClasses.FirstOrDefault();
                theLabelClass.Expression = $"$feature.{divFieldnameFac} + ' ' + $feature.{divNameFieldnameFac}";//set the label class Expression to use the Arcade expression
                facLayer.SetDefinition(def);
                facLayer.SetLabelVisibility(true);
            });

 @CharlesMacleod @UmaHarano @Wolf 

CharlesMacleod

i believe there is a LabelClasses collection property on the layer definition. I think all u need to do is set that. A label class also has a text symbol property I believe - so I think you could just set _that_ on the default classes if, similar to the issue with the renderer, the classes in the layer document are not equivalent to the data in the layer.