Tim,
You just need to set the new multiPoints spatialReference.
mp.spatialReference = evt.target.graphics[0].geometry.spatialReference;
Here is my test sample:
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="viewport" content="initial-scale=1, maximum-scale=1,user-scalable=no" />
<title>Drop Down Test</title>
<link rel="stylesheet" href="http://js.arcgis.com/3.13/dijit/themes/claro/claro.css">
<link rel="stylesheet" href="http://js.arcgis.com/3.13/dojo/resources/dojo.css">
<link rel="stylesheet" href="http://js.arcgis.com/3.13/esri/css/esri.css">
<script src="http://js.arcgis.com/3.13/"></script>
<style>
html,
body,
#mainWindow {
height: 100%;
width: 100%;
margin: 0;
padding: 0;
}
body {
background-color: #FFF;
overflow: hidden;
font-family: "Trebuchet MS";
}
</style>
<script>
var map;
require([
"esri/map",
"dojo/on",
"esri/tasks/query",
"esri/layers/FeatureLayer",
"esri/geometry/Multipoint",
"dojo/store/Memory",
"dojo/_base/array",
"dojo/_base/lang",
"esri/request",
"dojo/json",
"dojo/parser",
"dijit/layout/BorderContainer",
"dijit/layout/ContentPane",
"dijit/form/Button",
"dijit/form/ComboBox",
"dojo/domReady!"
], function(
Map, on, Query, FeatureLayer, Multipoint, Memory, array, lang, esriRequest, json, parser
) {
parser.parse();
map = new Map("map", {
basemap: "topo",
center: [-98.1883, 37.0868],
zoom: 5
});
var Points = new FeatureLayer("http://sampleserver6.arcgisonline.com/arcgis/rest/services/Census/MapServer/0", {
mode: FeatureLayer.MODE_SNAPSHOT,
outFields: ["*"]
});
var BlockGrp = new FeatureLayer("http://sampleserver6.arcgisonline.com/arcgis/rest/services/Census/MapServer/1", {
mode: FeatureLayer.MODE_SELECTION,
outFields: ["*"]
});
BlockGrp.setMinScale(0);
BlockGrp.setMaxScale(0);
Points.setDefinitionExpression("STATE_FIPS = '01' AND CNTY_FIPS = '015' AND BLOCK = '3039'");
Points.setMinScale(0);
Points.setMaxScale(0);
Points.on('update-end', function(evt){
var mp = new Multipoint();
array.map(evt.target.graphics, function(gra){
mp.addPoint(gra.geometry);
});
mp.spatialReference = evt.target.graphics[0].geometry.spatialReference;
console.info(mp);
var query = new Query();
query.geometry = mp;
BlockGrp.selectFeatures(query);
})
map.addLayers([Points, BlockGrp]);
BlockGrp.on('selection-complete', function (evt){
console.log(evt);
});
});
</script>
</head>
<body class="claro">
<div id="mainWindow" data-dojo-type="dijit/layout/BorderContainer" data-dojo-props="design:'headline', gutters:false" style="padding:0px;margin:0px;">
</div>
</body>
</html>