javascript - Angular 2 中的 Amcharts 点击事件不起作用

Question

这是我的代码库

        export class myComponent implements OnInit {
          minHist;
          maxHist;
        }

        public callAmcharts(whichFilterType:String){

                    this.amchart = AmCharts.makeChart( "chart", {
                      "type": "serial",
                      "theme": "light",
                      "dataProvider": this.TrendData,
                      "valueAxes": [ {
                        "gridColor": "#FFFFFF",
                        "gridAlpha": 0.2,
                        "dashLength": 0
                      }],
                      "gridAboveGraphs": true,
                      "startDuration": 1,
                      "graphs": [ {
                        "balloonText": "[[category]]: <b>[[value]]</b>",
                        "fillAlphas": 0.8,
                        "lineAlpha": 0.2,
                        "type": "column",
                        "valueField": "dCount",
                        "showHandOnHover":true
                      } ],

                      "chartCursor": {
                        "categoryBalloonEnabled": false,
                        "cursorAlpha": 0,
                        "zoomable": false
                      },
                      "categoryField": "dRange",
                      "categoryAxis": {
                        "gridPosition": "start",
                        "gridAlpha": 0,
                        "tickPosition": "start",
                        "tickLength": 20,
                        "labelRotation": 45
                      },
                      "export": {
                        "enabled": true
                      }

                    });

   this.amchart.addListener("clickGraphItem",this.myfunc);

}

现在 onclick 事件 myfunc 正在被调用。但奇怪的是，我无法使用 this 访问那里的任何全局变量。如果它是一个 scope 问题，那么在调用 myfunc 时应该会出错，对吗？

public myfunc(e:any){
        var range= e.item.category;
        let range_arr = range.split("-");
        this.minHist=range_arr[0];
        this.maxHist=range_arr[1];

    } 

我收到错误消息 Uncaught TypeError: Cannot set property 'minHist' of undefined

Answer 1

改变

this.amchart.addListener("clickGraphItem",this.myfunc);

至

this.amchart.addListener("clickGraphItem",this.myfunc.bind(this));

根据您的输入，这也将起作用:

this.amchart.addListener("clickGraphItem",(e)=> this.myfunc(e));

这是以下内容的较短版本:

this.amchart.addListener("clickGraphItem",(e)=> { return this.myfunc(e); });

建议阅读:How to access the correct `this` context inside a callback?