javascript - `this` 变量在 Angular2 TypeScript 中的 js 方法或包之外无法访问

Question

this 变量在 Angular2 TypeScript 中的 js 方法或包之外无法访问。

public mousekeyAction() {
            var mc=0,kc=0;           
        gkm.events.on('key.pressed', function (data) {
          this.keyscount= kc++;
          console.log(this.keyscount);
        });
        // Listen to all mouse events (click, pressed, released, moved, dragged)
        gkm.events.on('mouse.*', function (data) {
            this.mousecount=mc++;
           console.log(this.mousecount);
        });
    }

Answer 1

您必须使用粗箭头作为函数/回调而不是简单的函数。即使在函数之外，这也将维持 this 的范围。

像这样使用你的函数:-

public mousekeyAction() {
        var mc=0,kc=0;           
        gkm.events.on('key.pressed', (data) => {
            this.keyscount= kc++;
            console.log(this.keyscount);
        });
        // Listen to all mouse events (click, pressed, released, moved, dragged)
        gkm.events.on('mouse.*', (data) => {
            this.mousecount=mc++;
            console.log(this.mousecount);
        });
    }

有关更多信息，请参阅此处

• https://basarat.gitbooks.io/typescript/docs/arrow-functions.html