function HAPCexecuteQueryTask(fmc) { HAPCquery.where = "FisheryManagementCouncil = '"+ fmc +"'"; HAPCqueryTask.execute(HAPCquery,populateList); HAPCqueryTask.execute(HAPCquery,showResults); }
I want to zoom to a feature (graphic) when a user selects it from a dojo filtering select list. This list is populated using a queryTask. Is it okay to execute a second queryTask that takes the same results and does something else with it? function HAPCexecuteQueryTask(fmc) { HAPCquery.where = "FisheryManagementCouncil = '"+ fmc +"'"; HAPCqueryTask.execute(HAPCquery,populateList); HAPCqueryTask.execute(HAPCquery,showResults); }I have been looking at this example and it seems to be pretty close to what I want to do (see last entry for solution. http://forums.arcgis.com/threads/36317-Zoom-to-Graphic?highlight=graphics
Instead of two queries, why not add an onclick event to the item in the List that zooms to the geometry? (if you showed your populatelist /showresults functions, it would help)
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <title>State Info</title> <link rel="stylesheet" type="text/css" href="http://serverapi.arcgisonline.com/jsapi/arcgis/2.5/js/dojo/dijit/themes/tundra/tundra.css"> <script type="text/javascript">var dojoConfig = { parseOnLoad:true };</script> <script type="text/javascript" src="http://serverapi.arcgisonline.com/jsapi/arcgis/?v=2.5"></script> <script type="text/javascript"> dojo.require("esri.tasks.query"); dojo.require("dijit.form.Select"); dojo.require("dijit.form.FilteringSelect"); dojo.require("dojo.data.ItemFileReadStore"); dojo.require("dojo.parser"); var query, queryTask, map, hapcLayer; function init() { //create map and add layer map = new esri.Map("mapDiv"); var layer = new esri.layers.ArcGISDynamicMapServiceLayer("http://server.arcgisonline.com/ArcGIS/rest/services/Ocean_Basemap/MapServer"); map.addLayer(layer); hapcLayer = new esri.layers.ArcGISDynamicMapServiceLayer("http://egisws02.nos.noaa.gov/ArcGIS/rest/services/NMFS/HAPC/MapServer", { "id": "HAPC" }); map.addLayer(hapcLayer); hapcLayer.hide(); } //initialize query task queryTask = new esri.tasks.QueryTask("http://egisws02.nos.noaa.gov/ArcGIS/rest/services/NMFS/HAPC/MapServer/0"); //initialize HAPC query query = new esri.tasks.Query(); query.returnGeometry = true; query.outFields = ["HAPC_Sitename","FisheryManagementCouncil"]; function executeQueryTask(fmc) { //alert(fmc); //set query based on what user selected in from list; query.where = "FisheryManagementCouncil = '"+ fmc +"'"; //alert(query.where); //execute query queryTask.execute(query,populateList); } function populateList(results) { //Populate the dropdown list box with unique values var zone; var values = []; //create array var testValsEncountered={}; // create JSON object (dictionary) to hold multiple name:value pairs //Add option to display all zoning types to the dropdown list //values.push({name:"ALL"}); //All is not a value in the layer which is why it is being hard coded here. var features = results.features; //features is a property of query task and has the type of 'graphic'. It is an array. dojo.forEach (features, function(feature) { //optimized way of doing a for loop, specific to dojo, patterned after HTML5. Let's you apply a function to each element of an array. Feauture is each item in the array. zone = feature.attributes.HAPC_Sitename; //feature in this context is a graphic and attribute is a property if (!testValsEncountered[zone]) { //tests to see if the testval object containing the value of zone doesn't exist testValsEncountered[zone] = true; //creates a "key" zone with a value of true values.push({name:zone});//push the JSON pair into the values array } }); //sort function by Douglas Crockford, page 81, Javascript: The Good Parts var by = function(name){ return function (o,p) { var a,b; if (typeof o === 'object' && typeof p === 'object' && o && p) { a = o[name]; b = p[name]; if (a===b){ return o; } if (typeof a === typeof b){ return a < b ? -1 : 1; } return typeof a < typeof b ? -1 : 1; }else { throw { name: 'Error', message: 'Expected an object when sorting by ' + name }; } }; }; values.sort(by('name')); //sorts the array of unique values values.unshift({name:"ALL"}); //ensures that an ALL option is not part of the sort and is listed first //Create a ItemFileReadStore and use it for the ComboBox's data source var dataItems = { //create JSON object to hold multiple name:value pairs identifier: 'name', //optional label: 'name', //optional items: values }; var store = new dojo.data.ItemFileReadStore({data:dataItems}); dijit.byId("mySelect").store = store; } function applyLayerDef(selItem){ map.graphics.clear(); //Filter the layer to display only the selected HAPC feature if (selItem.value !== 'ALL') { var layerDefs = []; layerDefs[0] = "HAPC_Sitename = " + "'" + selItem.value + "'"; layerDefs.visibleLayers = [0]; map.getLayer("HAPC").setLayerDefinitions(layerDefs); hapcLayer.show(); } else { map.getLayer("HAPC").setDefaultLayerDefinitions(); hapcLayer.show(); } } dojo.addOnLoad(init); </script> <body class="tundra"> <br/> Select A Region : <select name="fmc2" id="fmc2" onChange="executeQueryTask(dojo.byId('fmc2').value);"> <option value="" selected="selected">Select Region</option> <option value="Mid-Atlantic Fishery Management Council">MAFMC</option> <option value="Gulf of Mexico Fishery Management Council">GFMC</option> </select> <select id="mySelect" dojotype="dijit.form.FilteringSelect" style="width:300px;font-size:18px;" autoComplete="true" forceValidOption="false" value="Select HAPC" onChange="applyLayerDef(this)"> </select> <div id="mapDiv" style="width:600px; height:600px; border:1px solid #000;"></div> </body> </html>
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