ExpandedState Property (BulkLayerCreationParams)
Gets and sets the layer expanded state for all layers. Default value is
LayerExpandedState.Default meaning that the expanded state of the layer is set according to the layer type. On creation, some layer types are expanded by default (for example FeatureLayers, CatalogLayers, TopologyLayers); other layer types are collapsed by default (for example TinLayers, TerrainLayers, ParcelLayers).
Target Platforms: Windows 11, Windows 10
ArcGIS Pro version: 3.6 or higher.