public Dictionary<T,List<long>> ToDictionary<T>()
where T: MapMember

// get the currently selected features in the map
var selectedFeatures = ArcGIS.Desktop.Mapping.MapView.Active.Map.GetSelection();
// get the first layer and its corresponding selected feature OIDs
var firstSelectionSet = selectedFeatures.ToDictionary().First();

// create an instance of the inspector class
var inspector = new ArcGIS.Desktop.Editing.Attributes.Inspector();
// load the selected features into the inspector using a list of object IDs
await inspector.LoadAsync(firstSelectionSet.Key, firstSelectionSet.Value);

QueuedTask.Run(() =>
{

  // get the currently selected features in the map
  var selectedFeatures = ArcGIS.Desktop.Mapping.MapView.Active.Map.GetSelection();

  // get the first layer and its corresponding selected feature OIDs
  var firstSelectionSet = selectedFeatures.ToDictionary().First();

  // create an instance of the inspector class
  var inspector = new ArcGIS.Desktop.Editing.Attributes.Inspector();

  // load the selected features into the inspector using a list of object IDs
  inspector.Load(firstSelectionSet.Key, firstSelectionSet.Value);

  //get the value of
  var pscode = inspector["STATE_NAME"];
  var myGeometry = inspector.Shape;
});

var selSetDict = selSet.ToDictionary();

// convert to the dictionary and only include those that are of type FeatureLayer
var selSetDictFeatureLayer = selSet.ToDictionary<FeatureLayer>();

var kvp = selSet.ToDictionary().Where(kvp => kvp.Key.Name == "LayerName").FirstOrDefault();
var oidList = kvp.Value;