public void Move( 
   SelectionSet features,
   double dx,
   double dy
)

//Get all of the selected ObjectIDs from the layer.
var firstLayer = MapView.Active.Map.GetLayersAsFlattenedList().OfType<FeatureLayer>().FirstOrDefault();
var selectionfromMap = firstLayer.GetSelection();

// set up a dictionary to store the layer and the object IDs of the selected features
var selectionDictionary = new Dictionary<MapMember, List<long>>();
selectionDictionary.Add(firstLayer as MapMember, selectionfromMap.GetObjectIDs().ToList());

var moveFeature = new EditOperation() { Name = "Move features" };
//at 2.x - moveFeature.Move(selectionDictionary, 10, 10);  //specify your units along axis to move the geometry
moveFeature.Move(SelectionSet.FromDictionary(selectionDictionary), 10, 10);  //specify your units along axis to move the geometry
if (!moveFeature.IsEmpty)
{
  var result = moveFeature.Execute(); //Execute and ExecuteAsync will return true if the operation was successful and false if not
}