Question

我想知道如何在匿名函数中访问和修改变量a，我尝试放箭头，但是我进入浏览器：未定义

 import * as Konva from 'konva';

export class classTest {

    public a: number;

    access(){ 

        var stage = new Konva.Stage({ container: 'container', width: 400, height: 250 });

        var layer1 = new Konva.Layer();
        var imageObj = new Image();
        var self = this
        imageObj.onload = function () {

            self.a = 150

            var yoda = new Konva.Image({
                x: 50,
                y: 50,
                image: imageObj,
                width: 106,
                height: 118
            });
            layer1.add(yoda);
            //stage.add(layer1)

        };
        imageObj.src = '/assets/images/yoda.jpg';
        //console.log(a)

如果我在layer1中添加一个width = a的矩形，它将与您解释的相同（我得到一条线），那么我该怎么做。

        var box = new Konva.Rect({
            x: 20, y: 20,
            width: this.a, 
            height: 50,
            fill: '#00D2FF', stroke: 'black',
            strokeWidth: 4
       });

       stage.add(layer1)
    }

Answer 1

SELECT *, .... AS membership FROM customer; +-----------+----+---------+----------+ |customer_id|name|telephone|membership| +-----------+----+---------+----------+ | 1 |Andi|+62932011| Plus | | 2 |Boby|+62928291| Regular | | 3 |Jane|+62932212| Regular | | 4 |John|+62999021| Regular | | 5 |Beth|+62999021| Regular | | 6 |Noel|+62999021| Plus | +-----------+----+---------+----------+

早于

执行

console.log(this.a);

这就是为什么您获得imageObj.onload

在undefined内部，一切正常。

修改函数变量中的变量

1 个答案: