***Just updated to add one more check and better variable naming***Been dealing with this myself -- and it's different between jsapi 2.x and 3.x. Only what's showing on map will be identified on. Note the checking of subLayerIds for null, scale checking, after getting the visibleLayers from service.Solution is for jaspi 3.x
function doIdentify(evt) {
var referenceLayer = new esri.layers.ArcGISDynamicMapServiceLayer(referenceMapServiceName, {id: 'referenceLayer'});
var aVisibleSubLayers = referenceLayer.visibleLayers,
aLayersInScale = [],
identifyParams = new esri.tasks.IdentifyParameters(),
identifyTask = new esri.tasks.IdentifyTask(referenceLayer.url);
//loop thru visible sublayers that are not group layers, then check within scale
if (referenceLayer.visible === true && aVisibleSubLayers.length !== 0 && aVisibleSubLayers[0] !== -1) {
dojo.forEach(referenceLayer.createDynamicLayerInfosFromLayerInfos(), function (dLayInfo) {
if (dLayInfo.subLayerIds === null && dojo.indexOf(aVisibleSubLayers, dLayInfo.id) !== -1 &&
(dLayInfo.minScale === undefined || dLayInfo.minScale === 0 || map.getScale() <= dLayInfo.minScale) &&
(dLayInfo.maxScale === undefined || dLayInfo.maxScale === 0 || map.getScale() >= dLayInfo.maxScale)) {
aLayersInScale.push(dLayInfo.id);
}
});
}
if (aLayersInScale.length > 0) {
identifyParams.geometry = evt.mapPoint;
identifyParams.mapExtent = map.extent;
identifyParams.tolerance = 3;
identifyParams.returnGeometry = true;
identifyParams.layerIds = aLayersInScale;
identifyParams.layerOption = esri.tasks.IdentifyParameters.LAYER_OPTION_ALL;
identifyParams.width = map.width;
identifyParams.height = map.height;
identifyTask.execute(identifyParams, function(idResults) {
doSomethingWithIdentifyResults(idResults);
});
}
}
Bonus: Identifies on multiple services at once and return as one array using dojo.DeferredList
dojo.require("dojo.DeferredList");
referenceLayer = new esri.layers.ArcGISDynamicMapServiceLayer(referenceMapServiceName, {id: 'referenceLayer'});
//Operational layers
operationalLayer = new esri.layers.ArcGISDynamicMapServiceLayer(operationalMapServiceName, {id: 'operationalLayer'});
function executeIdentify(geom, serviceName, aLayerIds) {
var identifyParams = new esri.tasks.IdentifyParameters(),
identifyTask = new esri.tasks.IdentifyTask(serviceName);
identifyParams.geometry = geom;
identifyParams.mapExtent = map.extent;
identifyParams.tolerance = 3;
identifyParams.returnGeometry = true;
identifyParams.layerIds = aLayerIds;
identifyParams.layerOption = esri.tasks.IdentifyParameters.LAYER_OPTION_ALL;
identifyParams.width = map.width;
identifyParams.height = map.height;
return identifyTask.execute(identifyParams);
}
function doIdentify(evt) {
var geom = evt.mapPoint,
aLayersInScale,
aDeferreds = [],
deferredList,
currentScale = map.getScale(),
aVisibleSubLayers,
aAGSDynMapServicesToIdentify = [referenceLayer, operationalLayer];
map.graphics.clear();
identifyLayerKeyPrevious = undefined;
//loop thru dynamic services, then thru visible sublayers that are not group layers, then check within scale
dojo.forEach(aAGSDynMapServicesToIdentify, function (agsDynMapService) {
aVisibleSubLayers = agsDynMapService.visibleLayers;
if (agsDynMapService.visible === true && aVisibleSubLayers.length !== 0 && aVisibleSubLayers[0] !== -1) {
aLayersInScale = [];
dojo.forEach(agsDynMapService.createDynamicLayerInfosFromLayerInfos(), function (dLayInfo) {
if (dLayInfo.subLayerIds === null && dojo.indexOf(aVisibleSubLayers, dLayInfo.id) !== -1 &&
(dLayInfo.minScale === undefined || dLayInfo.minScale === 0 || currentScale <= dLayInfo.minScale) &&
(dLayInfo.maxScale === undefined || dLayInfo.maxScale === 0 || currentScale >= dLayInfo.maxScale)) {
aLayersInScale.push(dLayInfo.id);
}
});
if (aLayersInScale.length > 0) {
aDeferreds.push(executeIdentify(evt.mapPoint, agsDynMapService.url, aLayersInScale));
}
}
});
// create a deferred list to aggregate the state for multiple asynchronous identify queries
deferredList = new dojo.DeferredList(aDeferreds);
deferredList.then(function (aIdentifyResults) {
// "aIdentifyResults" is 2D array of results
// array[0] boolean true or false, success or failure of individual call
// array[1] is the array of identity results returned
doSomethingWithIdentifyResults(aIdentifyResults);
});
}
