arcgis js加载天地图不执行load事件

define(["dojo/_base/declare",

        "esri/layers/TiledMapServiceLayer",

        "esri/geometry/Extent",

        "esri/SpatialReference",

        "esri/layers/TileInfo"],

    function (declare,TiledMapServiceLayer,Extent,SpatialReference,TileInfo) {

        return declare(TiledMapServiceLayer, {

            constructor: function () {

                this.spatialReference = new SpatialReference({ wkid: 4326 });

                this.initialExtent = (this.fullExtent = new Extent(-180.0, -90.0, 180.0, 90.0, this.spatialReference));

                this.tileInfo = new TileInfo({

                    "rows": 256,

                    "cols": 256,

                    "compressionQuality": 0,

                    "origin": {

                        "x": -180,

                        "y": 90

                    },

                    "spatialReference": {

                        "wkid": 4326

                    },

                    "lods": [

                        { "level": 2, "resolution": 0.3515625, "scale": 147748796.52937502 },

                        { "level": 3, "resolution": 0.17578125, "scale": 73874398.264687508 },

                        { "level": 4, "resolution": 0.087890625, "scale": 36937199.132343754 },

                        { "level": 5, "resolution": 0.0439453125, "scale": 18468599.566171877 },

                        { "level": 6, "resolution": 0.02197265625, "scale": 9234299.7830859385 },

                        { "level": 7, "resolution": 0.010986328125, "scale": 4617149.8915429693 },

                        { "level": 8, "resolution": 0.0054931640625, "scale": 2308574.9457714846 },

                        { "level": 9, "resolution": 0.00274658203125, "scale": 1154287.4728857423 },

                        { "level": 10, "resolution": 0.001373291015625, "scale": 577143.73644287116 },

                        { "level": 11, "resolution": 0.0006866455078125, "scale": 288571.86822143558 },

                        { "level": 12, "resolution": 0.00034332275390625, "scale": 144285.93411071779 },

                        { "level": 13, "resolution": 0.000171661376953125, "scale": 72142.967055358895 },

                        { "level": 14, "resolution": 8.58306884765625e-005, "scale": 36071.483527679447 },

                        { "level": 15, "resolution": 4.291534423828125e-005, "scale": 18035.741763839724 },

                        { "level": 16, "resolution": 2.1457672119140625e-005, "scale": 9017.8708819198619 },

                        { "level": 17, "resolution": 1.0728836059570313e-005, "scale": 4508.9354409599309 },

                        { "level": 18, "resolution": 5.3644180297851563e-006, "scale": 2254.4677204799655 }

                    ]

                });

                this.loaded = true;

                this.onLoad(this);

            },

            getTileUrl: function (level, row, col) {

                return "http://t" + col % 8 + ".tianditu.cn/vec_c/wmts?SERVICE=WMTS&REQUEST=GetTile&VERSION=1.0.0&LAYER=vec&STYLE=default&TILEMATRIXSET=c&TILEMATRIX=" + level + "&TILEROW=" + row + "&TILECOL=" + col + "&FORMAT=tiles";

            }

        });

    });

map = new Map("map", { logo: false });

var basemap = new TDTLayer();

map.addLayer(basemap);

map.on("load", function() {

	alert("load success");

});