利用 Task\Query 实现定位 , FeatureLayer 的属性查询

$利用 Task\Query 实现定位 , FeatureLayer 的属性查询$

放纵了几天，又有了学习的动力。今天实现了利用对 FeatureLayer 进行属性查询在地图上进行跳转。

　　一、我下载了一幅浙江省的县界面地图，存在NAME字段，利用Name就能进行查询了：

var name = tb.value;

if(name!="")

{

    var query = new esri.tasks.Query();

    query.where = "NAME = '"+name+"'";

    fl.queryFeatures(query, function (featureset) {

        var a =featureset.features[0].geometry.getExtent();

        map.setExtent(a);

    });

}

　　备注：FeatureLayer.queryFeatures 返回的不是 Feature 的一个集合，需要注意的是它本身就是单独的一个 Object ，而不是单纯的 Arry[] ，一开始没仔细看，半天取不出数据。不知道能不能进行模糊查询，希望可以，不然真的不方便啊。再试试...

　　二、很简单的例子给大家看看：

<!DOCTYPE html>

<html>

    <head>

        <meta charset="utf-8">

        <title>Query Demo</title>

        <link rel="stylesheet" href="http://js.arcgis.com/3.10/js/dojo/dijit/themes/tundra/tundra.css">

        <link rel="stylesheet" href="http://js.arcgis.com/3.10/js/esri/css/esri.css">

        <script type="text/javascript" charset="utf-8" src="http://js.arcgis.com/3.10/"></script>

        <script type="text/javascript" charset="utf-8" src="js/dojo.js"></script>

        <script type="text/javascript" charset="utf-8">

          require([

            "esri/map", "esri/layers/FeatureLayer",

            "esri/tasks/query", "esri/TimeExtent","esri/tasks/query",

            "dojo/number", "dojo/date/locale", "dojo/dom","dojo/on",

            "dojo/_base/array", "dojo/store/Memory",

            "dgrid/OnDemandGrid", "dojo/domReady!"

          ], function()

          {

              //初始化地图控件

              var map = new esri.Map("mapdiv");

              map.setBasemap("osm");

            var bounds = new esri.geometry.Extent({

              "xmin":118.363523,"ymin":29.219302,"xmax":119.508848,"ymax":30.073848,

              "spatialReference":{"wkid":4326}});

            map.setExtent(bounds);

            //初始化图层

            var durl = "http...MapServer";

            var dl = new esri.layers.ArcGISDynamicMapServiceLayer(durl);

            var furl = "http...MapServer/0";

            var fl = new esri.layers.FeatureLayer(furl,{outFields: ["*"],opacity: 0});

            map.addLayer(dl);

            map.addLayer(fl);

            //注册Go点击事件

            var btn = document.getElementById("query");

              btn.onclick = function(){

                  var tb = document.getElementById("val");

                    var name = tb.value;

                    if(name!="")

                    {

                        var query = new esri.tasks.Query();

                        query.where = "NAME = '"+name+"'";

                        fl.queryFeatures(query, function (featureset) {

                            var a =featureset.features[0].geometry.getExtent();

                            map.setExtent(a);

                        });

                    }

              }

          });

        </script>

    </head>

    <body>

        <div id="tolbox">

            Name:

            <input type="text" name="val" id="val" />

            <input type="button" name="query" id="query" value="Go" />

        </div>

        <div id="mapdiv" style="width: 600px; height: 600px; background-color: #FF8F8F;"></div>

    </body>

</html>

效果：

$利用 Task\Query 实现定位 , FeatureLayer 的属性查询$