How to fix TypeError: this._url is undefined in ArcGIS JS API (Query)

Question

我的任务是为 ArcGIS 的 Web App Builder 开发一个自定义小部件，我一直在尝试使用 ArcGIS Javascript API 3.28 使查询工作，以便我可以构建使用图层信息的报告。但是在尝试通过按钮测试查询时，我得到一个 TypeError: this._url is undefined.


define(['dojo/_base/declare', 'jimu/BaseWidget',
        'jimu/dijit/Report', 'esri/layers/FeatureLayer',
        'jimu/dijit/PageUtils', 'dijit/_WidgetsInTemplateMixin', 'esri/tasks/IdentifyTask',
        'esri/tasks/IdentifyParameters', 'esri/symbols/SimpleFillSymbol', 'esri/symbols/SimpleLineSymbol',
        'esri/graphic', 'esri/Color', 'dojo/_base/lang',
        'dojo/_base/html', 'dojo/on', 'dojo/domReady!',
        'esri/tasks/QueryTask', 'esri/tasks/query'],

function(declare, BaseWidget, Report, FeatureLayer,
        PageUtils, _WidgetsInTemplateMixin, IdentifyTask, IdentifyParameters,
        SimpleFillSymbol, SimpleLineSymbol, Graphic,
        Color, lang, on, Query, QueryTaskTest) {

  var baseWidgetClass = declare([BaseWidget], {
    baseClass: 'jimu-widget-demo',

    postCreate: function() { // POST CREATE!
      this.inherited(arguments);
      this.map.infoWindow.hide();
    },

    startup: function() {
      this.inherited(arguments);
      console.log('startup');
    },

    onClose: function(){
      console.log('onClose');
    },

    _onBtnPrintClicked: function(){
    console.log("Begin query test");
    var queryUrl = "https://webportalurl/arcgis/rest/services/ServiceName/MapServer/0";
    var queryTask = new QueryTaskTest(queryUrl);
    var query = new Query();
    query.returnGeometry = false;
    query.outFields = ["*"];
    query.where = "HAB_IPTU = 2089358";
    console.log("Running execute");

    queryTask.execute(query).then(function(results){
      console.log(results.features[0]);
    });
  }

  });
  return baseWidgetClass;
});

Answer 1

api 3.28 上的 QueryTask 期望 url 为 String：https://developers.arcgis.com/javascript/3/jsapi/querytask-amd.html#querytask1

试试这个：

var queryTask = new QueryTask(queryUrl);

或

var queryTask = new QueryTask("MapServerUrl");

Answer 2

该问题与 QueryTask 或您如何调用它无关。 define 语句和函数定义中的参数不匹配。

'dojo/_base/lang' 与函数中的 lang 匹配，然后 'dojo/_base/html' 与 on 匹配，'dojo/on' 与 Query 匹配，最后 'dojo/domReady!' 与查询任务测试。在定义列表的末尾使用不需要相应构造函数的模块，否则您必须将它们包含在函数定义中以保留顺序。

像这样

    define(['dojo/_base/declare',
        'jimu/BaseWidget',        
        'jimu/dijit/Report', 
        'esri/layers/FeatureLayer',
        'jimu/dijit/PageUtils',
        'dijit/_WidgetsInTemplateMixin',
        'esri/tasks/IdentifyTask',
        'esri/tasks/IdentifyParameters', 
        'esri/symbols/SimpleFillSymbol', 
        'esri/symbols/SimpleLineSymbol',
        'esri/graphic', 
        'esri/Color', 
        'dojo/_base/lang',
        'dojo/on',        
        'esri/tasks/query',
        'esri/tasks/QueryTask',
        'dojo/_base/html', //these last two are at the end
        'dojo/domReady!'], //because they don't need to be called or instantiated directly.

    function(declare, 
        BaseWidget, 
        Report, 
        FeatureLayer,
        PageUtils, 
        _WidgetsInTemplateMixin,
        IdentifyTask,
        IdentifyParameters,
        SimpleFillSymbol,
        SimpleLineSymbol,
        Graphic,
        Color,
        lang,
        on,
        Query,
        QueryTaskTest) { ....});

How to fix TypeError: this._url is undefined in ArcGIS JS API (Query)

How to fix TypeError: this._url is undefined in ArcGIS JS API (Query)

javascript

widget

arcgis-js-api