Dojo AMD模块更改了参考；这"；_Dojo_Amd

Dojo AMD模块更改了参考；这"；

dojo

Dojo AMD模块更改了参考；这"；,dojo,amd,Dojo,Amd,我真的很困惑，我在尝试学习AMD风格的Dojo时看到了一些行为。当我实例化模块/对象时，“this”指的是构造函数中的对象。我调用了一个内部函数，该内部函数中的“this”指的是窗口对象。因此，当我访问this.attachMapEventHandlers时，我得到一个“Object[Object global]没有方法'attachMapEventHandlers'”错误。我做错了什么？更新：我找到了lang.hitch，这似乎表明异步特性让我感到困惑，但我对如何实现解决方案感到困惑 inde

我真的很困惑，我在尝试学习AMD风格的Dojo时看到了一些行为。当我实例化模块/对象时，“this”指的是构造函数中的对象。我调用了一个内部函数，该内部函数中的“this”指的是窗口对象。因此，当我访问this.attachMapEventHandlers时，我得到一个“Object[Object global]没有方法'attachMapEventHandlers'”错误。我做错了什么？更新：我找到了lang.hitch，这似乎表明异步特性让我感到困惑，但我对如何实现解决方案感到困惑

index.html中的我的脚本：

require(["javascript/layout", "dijit/layout/ContentPane", "dijit/layout/BorderContainer", "dijit/layout/AccordionContainer", 
        "dojo/dom", "dojo/dom-attr", "dijit/Toolbar", "dijit/form/Button", "dijit/Dialog","dijit/ProgressBar", "dojo/domReady!"],
        function (layout, dom, domAttr) {
            mapControl = new layout();

layout.js：

define(["dojo/_base/declare"], function(declare) {
return declare(null, {
    action:"pan",
    activeMeasureTool:"",
    aerialLayer:"",
    legendLayers:"",
    loadedServices:"",
    popup:"",
    resizeId:0,
    constructor: function() {
        this.init();
    },
    init: function() {
        require(["esri/map", "esri/config", "esri/SpatialReference", "esri/geometry/Extent"], 
            function(Map, config, SpatialReference, Extent) {
            //custom map requires a proxy to function properly.
            esri.config.defaults.io.proxyUrl = "../sdc_devdata/proxy.php";

            var spatRef = new SpatialReference(2276);

            var startExtent = new Extent(2481416.32087491, 6963246.42495962, 2501196.36936991, 6980267.92469462, spatRef);
            var appFullExtent = new Extent(2396699.46935379, 6872369.60195443, 2607745.94404633, 7107335.22319087, spatRef);

            map = new Map("map", {extent: startExtent, isZoomSlider:true, logo:false, sliderStyle:"large"});
            this.attachMapEventHandlers();
            this.createLayers();
            this.handleLayerVisibilityChange();
        });
    },

你可以把“this”放在另一个变量中，比如这个，然后在你的内部函数中使用这个，比如

init: function() {
         var _this= this;
        require(["esri/map", "esri/config", "esri/SpatialReference", "esri/geometry/Extent"], 
            function(Map, config, SpatialReference, Extent) {
            ...
            _this.attachMapEventHandlers();
            _this.createLayers();
            _this.handleLayerVisibilityChange();

你可以把“this”放在另一个变量中，比如这个，然后在你的内部函数中使用这个，比如

init: function() {
         var _this= this;
        require(["esri/map", "esri/config", "esri/SpatialReference", "esri/geometry/Extent"], 
            function(Map, config, SpatialReference, Extent) {
            ...
            _this.attachMapEventHandlers();
            _this.createLayers();
            _this.handleLayerVisibilityChange();

你可以做一些事情来解决这个问题

首先，您可以将所需的依赖项添加到

define

数组中，这样就不需要在类的构造函数中执行异步require

这看起来像：

define(["dojo/_base/declare", "esri/map", "esri/config", "esri/SpatialReference", "esri/geometry/Extent"], function (declare, Map, config, SpatialReference, Extent) {
  return declare(null, {
    action: "pan",
    activeMeasureTool: "",
    aerialLayer: "",
    legendLayers: "",
    loadedServices: "",
    popup: "",
    resizeId: 0,
    constructor: function () {
      this.init();
    },
    init: function () {
      //custom map requires a proxy to function properly.
      esri.config.defaults.io.proxyUrl = "../sdc_devdata/proxy.php";

      var spatRef = new SpatialReference(2276);

      var startExtent = new Extent(2481416.32087491, 6963246.42495962, 2501196.36936991, 6980267.92469462, spatRef);
      var appFullExtent = new Extent(2396699.46935379, 6872369.60195443, 2607745.94404633, 7107335.22319087, spatRef);

      map = new Map("map", {
        extent: startExtent,
        isZoomSlider: true,
        logo: false,
        sliderStyle: "large"
      });
      this.attachMapEventHandlers();
      this.createLayers();
      this.handleLayerVisibilityChange();
    }
  });
});

或者，您可以在执行require时将

this

的当前范围保存到闭包中的某个内容

init: function () {
  var that = this;
  require(["esri/map", "esri/config", "esri/SpatialReference", "esri/geometry/Extent"],
    function (Map, config, SpatialReference, Extent) {
      //custom map requires a proxy to function properly.
      esri.config.defaults.io.proxyUrl = "../sdc_devdata/proxy.php";

      var spatRef = new SpatialReference(2276);

      var startExtent = new Extent(2481416.32087491, 6963246.42495962, 2501196.36936991, 6980267.92469462, spatRef);
      var appFullExtent = new Extent(2396699.46935379, 6872369.60195443, 2607745.94404633, 7107335.22319087, spatRef);

      map = new Map("map", {
        extent: startExtent,
        isZoomSlider: true,
        logo: false,
        sliderStyle: "large"
      });
      that.attachMapEventHandlers();
      that.createLayers();
      that.handleLayerVisibilityChange();
    });
},

编辑：第三个选项是使用lang.hitch，它允许您在回调函数中指定

this

的范围。要使用它，您需要将

dojo/_base/lang

添加到define（）依赖项列表中，并将require回调包装在

lang.hitch中（这个函数是（）{}）
我强烈建议使用第一个选项，因为它与AMD的整个使用是一致的（在执行之前声明模块需要什么依赖项，而不是动态加载它）。
要解决这个问题，您可以做几件事
首先，您可以将所需的依赖项添加到define
数组中，这样就不需要在类的构造函数中执行异步require
这看起来像：
define(["dojo/_base/declare", "esri/map", "esri/config", "esri/SpatialReference", "esri/geometry/Extent"], function (declare, Map, config, SpatialReference, Extent) {
  return declare(null, {
    action: "pan",
    activeMeasureTool: "",
    aerialLayer: "",
    legendLayers: "",
    loadedServices: "",
    popup: "",
    resizeId: 0,
    constructor: function () {
      this.init();
    },
    init: function () {
      //custom map requires a proxy to function properly.
      esri.config.defaults.io.proxyUrl = "../sdc_devdata/proxy.php";

      var spatRef = new SpatialReference(2276);

      var startExtent = new Extent(2481416.32087491, 6963246.42495962, 2501196.36936991, 6980267.92469462, spatRef);
      var appFullExtent = new Extent(2396699.46935379, 6872369.60195443, 2607745.94404633, 7107335.22319087, spatRef);

      map = new Map("map", {
        extent: startExtent,
        isZoomSlider: true,
        logo: false,
        sliderStyle: "large"
      });
      this.attachMapEventHandlers();
      this.createLayers();
      this.handleLayerVisibilityChange();
    }
  });
});

或者，您可以在执行require时将this
的当前范围保存到闭包中的某个内容
init: function () {
  var that = this;
  require(["esri/map", "esri/config", "esri/SpatialReference", "esri/geometry/Extent"],
    function (Map, config, SpatialReference, Extent) {
      //custom map requires a proxy to function properly.
      esri.config.defaults.io.proxyUrl = "../sdc_devdata/proxy.php";

      var spatRef = new SpatialReference(2276);

      var startExtent = new Extent(2481416.32087491, 6963246.42495962, 2501196.36936991, 6980267.92469462, spatRef);
      var appFullExtent = new Extent(2396699.46935379, 6872369.60195443, 2607745.94404633, 7107335.22319087, spatRef);

      map = new Map("map", {
        extent: startExtent,
        isZoomSlider: true,
        logo: false,
        sliderStyle: "large"
      });
      that.attachMapEventHandlers();
      that.createLayers();
      that.handleLayerVisibilityChange();
    });
},

编辑：第三个选项是使用lang.hitch，它允许您在回调函数中指定this
的范围。要使用它，您需要将dojo/_base/lang
添加到define（）依赖项列表中，并将require回调包装在lang.hitch中（这个函数是（）{}）
我强烈建议使用第一个选项，因为它与AMD的整个使用是一致的（在执行之前声明模块需要哪些依赖项，而不是动态加载）。
我感谢您的回答。我接受了第一个我感谢你的回答。我接受了第一个