ArcGIS Pro SDK Right-click to get the selected layer

need:

Get the layer selected by right click

Solution:

Get the selected graphic from the map page

// 获取所选要素
var firstFeatureLayer = MapView.Active.Map.GetLayersAsFlattenedList().OfType<FeatureLayer>().FirstOrDefault();

Get the selected map frame on the layout page

Layout layout = LayoutView.Active.Layout;
MapFrame mapFrame = LayoutView.Active.GetSelectedElements().FirstOrDefault() as MapFrame;