public class RasterLayerCreationParams : LayerCreationParams 

{
    // Create a new stretch colorizer definition using default constructor.
    StretchColorizerDefinition stretchColorizerDef = new StretchColorizerDefinition();
    // Create a raster layer creation parameters object with the raster file path.
    var rasterLayerCreationParams = new RasterLayerCreationParams(new Uri("rasterPath"))
    {
        ColorizerDefinition = stretchColorizerDef,
        Name = "rasterLayerName",
        MapMemberIndex = 0
    };

    // 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.
    //Note: Run within a QueuedTask
    RasterLayer rasterLayerfromURL =
  LayerFactory.Instance.CreateLayer<RasterLayer>(rasterLayerCreationParams, map);

}

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

    };
    // 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.
    //Note: Run within a QueuedTask
    MosaicLayer newMosaicLayer = LayerFactory.Instance.CreateLayer<MosaicLayer>(rasterLayerCreationParams, map);
}

{
    // Create a new colorizer definition using default constructor.
    StretchColorizerDefinition stretchColorizerDef = new StretchColorizerDefinition();
    var rasterLayerCreationParams = new RasterLayerCreationParams(new Uri(url))
    {
        Name = "RasterLayer",
        ColorizerDefinition = stretchColorizerDef,
        MapMemberIndex = 0
    };
    // Create an image service layer using the colorizer definition created above.
    //Note: Run within a QueuedTask
    ImageServiceLayer imageServiceLayerWithColorizer =
  LayerFactory.Instance.CreateLayer<ImageServiceLayer>(rasterLayerCreationParams, map);
}