In a ArcGISDynamicMapServiceLayer layer there is way to hide labels but it doesn't seem to be working correctly. I set the LayerDrawingOptions.ShowLabels to false and it still shows the labels on the map.
Code:
ArcGISDynamicMapServiceLayer layer = Map.layers[0];
DynamicLayerInfoCollection layerInfos = layer.CreateDynamicInfosFromlayerInfos();
layer.DrawingOptions = new LayerDrawingOptionsCollections(); //why is this null to start with?
foreach(DynamicLayerInfo layerInfo in layerInfos)
{
LayerDrawingOptions options = new LayerDrawingOptions();
option.LayerID = layerInfo.ID;
option.ShowLabels = false;
layer.LayerDrawingOptions.add(option);
}