Question

我目前正在尝试访问我的依赖关系链中特定祖先的方法。具体来说，我想从我初始化的GrandChildClass中运行ParentClass.logName()。这就是我访问ParentClass原型的方法（从Get parent class name from child with ES6?获取的方法）。

＆＃13;

class AncestorClass {
    constructor (name, id){
        this.name = name + id;
    }
    logName () {
        console.log(this.name);
    }
    
}

class ParentClass extends AncestorClass {
    constructor (name, id) {
        super(name, 1);
        this.name = name + id;
    }
}

class ChildClass extends ParentClass {
    constructor (name, id) {
        super(name, 2);
        this.name = name + id;
    }
}

class GrandchildClass extends ChildClass {
    constructor (name, id){
        super(name, 3);
        this.name = name + id;
    }
}

const grandchild = new GrandchildClass('testName', 4);
const parent =  Object.getPrototypeOf((Object.getPrototypeOf(grandchild.constructor)));
console.log(parent);
const initParent = new parent();
initParent.logName();

＆＃13;

所以我得到了原型并使用new关键字对其进行了初始化，但出于某种原因，initParent.logName()会返回NaN。

那么如何在没有直接初始化ParentClass的情况下从孙子中调用ParentClass.logName？

Answer 1

使用空构造函数初始化父级，这意味着属性为int foregroundNbackground(VideoCapture cap){ int count=0; vector<Mat> img_bg; Mat img, img_diff, b1; Mat Background = T12(cap); // This calculates the average of previous 100 frames and make it the background model imshow("Model", Background); while(1){ cap >> img; if(count < 100){ img_bg.push_back(img); } if(count == 100){ Background = getMean(img_bg); cvtColor(Background, b1, CV_BGR2GRAY); imshow("Model", b1); count = 0; img_bg.clear(); } absdiff(img, Background, img_diff); count++; cvtColor(img_diff,img_diff, CV_BGR2GRAY); threshold(img_diff,img_diff,80,255, CV_THRESH_BINARY); imshow("Task13", img_diff); waitKey(33); } }，undefined为undefined + undefined。

NaN

const initParent = new parent('foo', 1);
initParent.logName() // print 'foo1'

特定祖先的访问方法

1 个答案: