Garey,
Here is a full sample for dynamically changing the ArcGISDynamicMapServiceLayer's label field:
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="initial-scale=1, maximum-scale=1,user-scalable=no">
<title></title>
<link rel="stylesheet" href="http://js.arcgis.com/3.15/dijit/themes
<link rel="stylesheet" href="http://js.arcgis.com/3.15/esri/css/esri.css">
<style>
html,
body {
height: 100%;
width: 100%;
margin: 0;
padding: 0;
}
h3 {
margin: 0 0 5px 0;
border-bottom: 1px solid #444;
text-align: center;
}
.shadow {
-moz-box-shadow: 0 0 5px #888;
-webkit-box-shadow: 0 0 5px #888;
box-shadow: 0 0 5px #888;
}
#map {
margin: 0;
padding: 0;
}
#feedback {
background: #fff;
color: #444;
font-family: arial;
left: 30px;
margin: 5px;
padding: 10px;
position: absolute;
top: 30px;
width: 300px;
z-index: 40;
}
#note {
font-size: 80%;
font-weight: 700;
padding: 0 0 10px 0;
}
#loading {
visibility: hidden;
}
#legendDiv {
padding: 10px 0 0 0;
}
</style>
<script src="http://js.arcgis.com/3.15/"></script>
<script>
var app = {};
require([
"esri/map", "esri/layers/ArcGISTiledMapServiceLayer", "esri/layers/ArcGISDynamicMapServiceLayer",
"esri/request", "esri/config", "esri/tasks/ClassBreaksDefinition", "esri/tasks/AlgorithmicColorRamp",
"esri/tasks/GenerateRendererParameters", "esri/tasks/GenerateRendererTask",
"esri/layers/LayerDrawingOptions", "esri/layers/LabelClass", "esri/symbols/TextSymbol",
"esri/symbols/SimpleFillSymbol", "esri/dijit/Legend",
"dojo/parser", "dojo/_base/array", "esri/Color", "dojo/dom-style",
"dojo/json", "dojo/dom", "dojo/data/ItemFileReadStore", "dijit/registry",
"dijit/layout/BorderContainer", "dijit/layout/ContentPane", "dijit/form/FilteringSelect",
"dojo/domReady!"
], function (
Map,
ArcGISTiledMapServiceLayer, ArcGISDynamicMapServiceLayer,
esriRequest, esriConfig,
ClassBreaksDefinition, AlgorithmicColorRamp,
GenerateRendererParameters, GenerateRendererTask,
LayerDrawingOptions, LabelClass, TextSymbol,
SimpleFillSymbol, Legend,
parser, arrayUtils, Color, domStyle,
JSON, dom,
ItemFileReadStore,
registry
) {
parser.parse();
app.dataUrl = "http://sampleserver6.arcgisonline.com/arcgis/rest/services/Census/MapServer/2";
app.defaultFrom = "#ffffcc";
app.defaultTo = "#006837";
app.map = new Map("map", {
center: [-85.787, 39.782],
zoom: 9,
slider: false
});
var basemap = new ArcGISTiledMapServiceLayer("http://services.arcgisonline.com/ArcGIS/rest/services/World_Terrain_Base/MapServer");
app.map.addLayer(basemap);
var ref = new ArcGISTiledMapServiceLayer("http://services.arcgisonline.com/ArcGIS/rest/services/Reference/World_Reference_Overlay/MapServer");
urlDyn = "http://sampleserver6.arcgisonline.com/arcgis/rest/services/Census/MapServer";
usaLayer = new ArcGISDynamicMapServiceLayer(urlDyn, {
id: "us_counties",
opacity: 0.7,
visible: false
});
usaLayer.setVisibleLayers([2]);
app.map.addLayer(usaLayer);
var countyFields = esriRequest({
url: app.dataUrl,
content: {
f: "json"
},
callbackParamName: "callback"
});
countyFields.then(function (resp) {
var fieldNames, fieldStore;
fieldNames = {
identifier: "value",
label: "name",
items: []
};
arrayUtils.forEach(resp.fields.slice(6, 16), function (f) {
fieldNames.items.push({
"name": f.name,
"value": f.name
});
});
fieldStore = new ItemFileReadStore({
data: fieldNames
});
registry.byId("fieldNames").set("store", fieldStore);
registry.byId("fieldNames").set("value", "POP2007");
}, function (err) {
console.log("failed to get field names: ", err);
});
usaLayer.on("update-end", function () {
domStyle.set("loading", "visibility", "hidden");
});
registry.byId("fieldNames").on("change", getData);
registry.byId("fieldNames").set("value", "POP_2007");
function getData() {
var optionsArray = [];
var drawingOptions = new LayerDrawingOptions();
var labelClass = new LabelClass({
labelExpression: '[' + (registry.byId("fieldNames").get("value") || "POP2000") + ']',
labelPlacement: 'esriServerPolygonPlacementAlwaysHorizontal',
symbol: new TextSymbol()
});
drawingOptions.labelingInfo = [labelClass];
drawingOptions.showLabels = true;
optionsArray[2] = drawingOptions;
app.map.getLayer("us_counties").setLayerDrawingOptions(optionsArray);
app.map.getLayer("us_counties").show();
}
function errorHandler(err) {
console.log("error: ", JSON.stringify(err));
}
});
</script>
</head>
<body class="tundra">
<div data-dojo-type="dijit/layout/BorderContainer" data-dojo-props="design:'headline',gutters:false" style="width: 100%; height: 100%; margin: 0;">
<div id="map" data-dojo-type="dijit/layout/ContentPane" data-dojo-props="region:'center'">
<div id="feedback" class="shadow">
<h3>Change the Attribute Field Used to Render Data</h3>
<div id="info">
<div id="note">
Note: This sample requires an ArcGIS Server version 10.1 map service to generate a renderer.
</div>
<!-- filtering select -->
<label for="fieldNames">Render based on: </label>
<select id="fieldNames" name="baseSym" data-dojo-type="dijit/form/FilteringSelect" data-dojo-props="style:'width:200px;'">
</select>
<img id="loading" src="http://dl.dropbox.com/u/2654618/loading_black.gif" />
<div id="legendDiv"></div>
</div>
</div>
</div>
</div>
</body>
</html>
