Derek is correct you need the object id. Here's an example:
<html>
<head>
<link rel="stylesheet" type="text/css" href="http://serverapi.arcgisonline.com/jsapi/arcgis/2.6/js/dojo/dijit/themes/claro/claro.css">
<script src="http://serverapi.arcgisonline.com/jsapi/arcgis/?v=2.6" type="text/javascript"></script>
<script type="text/javascript">
dojo.require("esri.map");
dojo.require("esri.layers.FeatureLayer");
var map = null;
var featureLayer = null;
function init() {
map = new esri.Map("map", {
extent: new esri.geometry.Extent({
xmin: -1040766.5771306533,
ymin: 7095190.713541364,
xmax: -766204.7715304322,
ymax: 7278028.085199418,
spatialReference: {
wkid: 102100
}
})
});
// for webmaps
var arcgisURL = "http://server.arcgisonline.com/ArcGIS/rest/services/World_Topo_Map/MapServer"
// 102100
var tiledMapServiceLayer = new esri.layers.ArcGISTiledMapServiceLayer(arcgisURL);
map.addLayer(tiledMapServiceLayer);
}
function createFeatureLayer() {
var jsonFS = {
"geometryType": "esriGeometryPoint",
"features": [
{
"attributes": {
"Name": "Point1",
"ObjectID": 1
},
"geometry": {
"x": -958520.3346958433,
"y": 7120873.555045171
}
},
{
"attributes": {
"Name": "Point2",
"ObjectID": 2
},
"geometry": {
"x": -803811.7894467209,
"y": 7122708.0437240143
}
},
{
"attributes": {
"Name": "Point3",
"ObjectID": 3
},
"geometry": {
"x": -782409.4215268819,
"y": 7208317.51540337
}
},
{
"attributes": {
"Name": "Point4",
"ObjectID": 4
},
"geometry": {
"x": -1017529.720531971,
"y": 7189666.8805017965
}
}
]
};
var fs = new esri.tasks.FeatureSet(jsonFS);
var fsCollect = new esri.tasks.FeatureSet();
var featuresList = fs.features;
var layerDefinition = {
"displayFieldName": "Name",
"geometryType": "esriGeometryPoint",
"spatialReference": {
"wkid": 102100
},
"fields": [{
"name": "ObjectID",
"alias": "ObjectID",
"type": "esriFieldTypeOID"
}, {
"name": "Name",
"type": "esriFieldTypeString",
"alias": "Name"
}]
}
var featureCollection = {
layerDefinition: layerDefinition,
featureSet: fs
};
//alert(featureCollection.featureSet.features.length);
console.log(featureCollection);
featureLayer = new esri.layers.FeatureLayer(featureCollection);
var defaultSymbol = new esri.symbol.SimpleMarkerSymbol();
var renderer = new esri.renderer.UniqueValueRenderer(defaultSymbol, "Name");
//add symbol for each possible value
renderer.addValue("Point1", new esri.symbol.SimpleMarkerSymbol().setColor(new dojo.Color([255, 0, 0, 0.5])));
renderer.addValue("Point2", new esri.symbol.SimpleMarkerSymbol().setColor(new dojo.Color([0, 255, 0, 0.5])));
renderer.addValue("Point3", new esri.symbol.SimpleMarkerSymbol().setColor(new dojo.Color([0, 0, 255, 0.5])));
renderer.addValue("Point4", new esri.symbol.SimpleMarkerSymbol().setColor(new dojo.Color([255, 0, 255, 0.5])));
featureLayer.setRenderer(renderer);
map.addLayer(featureLayer);
dojo.connect(map, 'onClick', function (e) {
console.log(e.mapPoint.x + " " + e.mapPoint.y);
});
}
function checkNoRecords() {
if (featureLayer != null) {
alert("Number of records " + featureLayer.graphics.length);
} else alert("Feature Layer is null");
}
function getExtent() {
document.write("MinX: " + map.extent.xmin + " MinY: " + map.extent.ymin + " MaxX: " + map.extent.xmax + " MaxY: " + map.extent.ymax);
}
dojo.addOnLoad(init);
</script>
</head>
<body class='claro'>
<div id="map" style="width:900px; height:600px; border:1px solid #000;"></div>
<button onclick="createFeatureLayer()">Create Feature Layer</button>
<button onclick="checkNoRecords()">Check number of records in featurelayer</button>
</body>
</html>
