public ParcelEditToken CopyLineFeaturesToParcelType( 
   Layer sourceLayer,
   IEnumerable<long> sourceOIDs,
   Layer destinationLineLayer,
   Layer destinationPolygonLayer
)

string errorMessage = await QueuedTask.Run( async () =>
{
  // check for selected layer
  if (MapView.Active.GetSelectedLayers().Count == 0)
    return "Please select a target parcel polygon layer in the table of contents.";
  //get the feature layer that's selected in the table of contents
  var destPolygonL = MapView.Active.GetSelectedLayers().OfType<FeatureLayer>().FirstOrDefault();
  try
  {
    var myParcelFabricLayer = MapView.Active.Map.GetLayersAsFlattenedList().OfType<ParcelLayer>().FirstOrDefault();
    //if there is no fabric in the map then bail
    if (myParcelFabricLayer == null)
      return "There is no fabric in the map.";
    var pRec = myParcelFabricLayer.GetActiveRecord();
    if (pRec == null)
      return "There is no Active Record. Please set the active record and try again.";
    string ParcelTypeName = "";
    IEnumerable<string> parcelTypeNames = await myParcelFabricLayer.GetParcelTypeNamesAsync();
    foreach (string parcelTypeNm in parcelTypeNames)
    {
      var polygonLyrParcelTypeEnum = await myParcelFabricLayer.GetParcelPolygonLayerByTypeNameAsync(parcelTypeNm);
      foreach (FeatureLayer lyr in polygonLyrParcelTypeEnum)
        if (lyr == destPolygonL)
        {
          ParcelTypeName = parcelTypeNm;
          break;
        }
    }
    if (String.IsNullOrEmpty(ParcelTypeName))
      return "Please select a target parcel polygon layer in the table of contents.";
    var srcFeatLyr = MapView.Active.Map.GetLayersAsFlattenedList().OfType<FeatureLayer>().FirstOrDefault(l => l.Name.Contains("MySourceLines") && l.IsVisible);
    if (srcFeatLyr == null)
      return "Looking for a layer named 'MySourceLines' in the table of contents.";
    //now get the line layer for this parcel type
    var destLineLyrEnum = await myParcelFabricLayer.GetParcelLineLayerByTypeNameAsync(ParcelTypeName);
    if (destLineLyrEnum.Count() == 0) //make sure there is one in the map
      return ParcelTypeName + " not found.";
    var destLineL = destLineLyrEnum.FirstOrDefault();
    if (destLineL == null || destPolygonL == null)
      return "";
    var editOper = new EditOperation()
    {
      Name = "Copy Line Features To Parcel Type",
      ProgressMessage = "Copy Line Features To Parcel Type...",
      ShowModalMessageAfterFailure = true,
      SelectNewFeatures = true,
      SelectModifiedFeatures = false
    };
    var ids = new List<long>((srcFeatLyr as FeatureLayer).GetSelection().GetObjectIDs());
    if (ids.Count == 0)
      return "No selected lines were found. Please select line features and try again.";
    editOper.CopyLineFeaturesToParcelType(srcFeatLyr, ids, destLineL, destPolygonL);
    if (!editOper.Execute())
      return editOper.ErrorMessage;
  }
  catch (Exception ex)
  {
    return ex.Message;
  }
  return "";
});
if (!string.IsNullOrEmpty(errorMessage))
  MessageBox.Show(errorMessage, "Copy Line Features To Parcel Type.");