javascript - Angular/Typescript 无法设置未定义的属性 'data'

Question

我有一些代码正在读取 xml 然后解析数据。

所以这是代码:

data = [];

  ngOnInit() {
  this.myService.getData().subscribe(XMLResult => {
    const parseString = require('xml2js').parseString;
    parseString(XMLResult, function (err, result) {
       console.dir(result.listResponse.instance); // Returns Array
       this.data = result.listResponse.instance; // Here's the line giving me the error
    });

 });
}

Console.log 返回的数据如下:

Array(10)
  0:
   $: {id: "23" name: "name 1"}
  1:
   $: {id: "45" name: "name 2"}

等等

如何解决这个问题？

Answer 1

在您当前的方法中，this 不再引用您的组件。

修改您的回调以使用箭头函数，这样您就不会失去范围:

parseString(XMLResult, (err, result) => {
  console.dir(result.listResponse.instance);
  this.data = result.listResponse.instance;
})

Docs

Until arrow functions, every new function defined its own this value (a new object in the case of a constructor, undefined in strict mode function calls, the base object if the function is called as an "object method", etc.). This proved to be less than ideal with an object-oriented style of programming.