arcgis for js栅格图层叠加(Raster Layer)问题(2)

var layer = new ArcGISDynamicMapServiceLayer(http://192.168.0.225:6080/arcgis/rest/services/HN_test/MapServer);

if (layer.loaded) {
 buildSubLayerList(layer);
}
else {
 dojo.connect(layer, "onLoad", buildSubLayerList);
} 
function buildSubLayerList(layer) {
 var visible = [];
 dojo.map(layer.layerInfos,function (info, index) {
  if(符合条件) visible.push(info.id);
 });
 map.addLayer(layer);//万事俱备，至此方才将图层添加到地图
}