public class RasterLayerCreationParams : LayerCreationParams 

  // Create a new stretch colorizer definition using default constructor.
  StretchColorizerDefinition stretchColorizerDef = new StretchColorizerDefinition();
  var rasterLayerCreationParams = new RasterLayerCreationParams(new Uri(url))
  {
    ColorizerDefinition = stretchColorizerDef,
    Name = layerName,
    MapMemberIndex = 0
  };
  await QueuedTask.Run(() =>
  {
    // Create a raster layer using the colorizer definition created above.
    // Note: You can create a raster layer from a url, project item, or data connection.
    RasterLayer rasterLayerfromURL =
LayerFactory.Instance.CreateLayer<RasterLayer>(rasterLayerCreationParams, aMap);
  });

  // Create a new colorizer definition using default constructor.
  StretchColorizerDefinition stretchColorizerDef = new StretchColorizerDefinition();
  var rasterLayerCreationParams = new RasterLayerCreationParams(new Uri(url))
  {
    Name = layerName,
    ColorizerDefinition = stretchColorizerDef,
    MapMemberIndex = 0

  };
  await QueuedTask.Run(() =>
  {
    // Create a mosaic layer using the colorizer definition created above.
    // Note: You can create a mosaic layer from a url, project item, or data connection.
    MosaicLayer newMosaicLayer =
LayerFactory.Instance.CreateLayer<MosaicLayer>(rasterLayerCreationParams, aMap);
  });

  // Create a new colorizer definition using default constructor.
  StretchColorizerDefinition stretchColorizerDef = new StretchColorizerDefinition();
  var rasterLayerCreationParams = new RasterLayerCreationParams(new Uri(url))
  {
    Name = layerName,
    ColorizerDefinition = stretchColorizerDef,
    MapMemberIndex = 0
  };
  await QueuedTask.Run(() =>
  {
    // Create an image service layer using the colorizer definition created above.
    ImageServiceLayer imageServiceLayer =
LayerFactory.Instance.CreateLayer<ImageServiceLayer>(rasterLayerCreationParams, aMap);
  });