无法从angular4中的嵌套函数访问它

I have a component called abc and in that component I have three variable named title,Desc,Name and when I am trying to access it from nested function it gives me as undefined.

我有一个名为abc的组件，在该组件中我有三个名为title，Desc，Name的变量，当我尝试从嵌套函数访问它时，它给我一个未定义的。

e.g.

例如

@Component({
  selector: 'abc',
  templateUrl: './abc.component.html',
  styleUrls: ['./abc.component.css'],
  providers: [abcService]
})

export class abcComponent implements AfterViewInit,AfterViewChecked {

  title;
  Desc;
  Name;
  date=null;

test(){
this.title='a';
//work fine
}

test11(){

$('#cmg tbody').on('click', 'a.editor_edit', function (e) {
e.preventDefault();
this.title= false;  //gives me an undefined
});

}

}

1 个解决方案

#1

This is because you are losing the scope in your callback. Modify it to use an arrow function so that you keep this

这是因为您正在丢失回调中的范围。修改它以使用箭头功能，以便保持这一点

$('#cmg tbody').on('click', 'a.editor_edit', (e) => {
  e.preventDefault();
  this.title= false;
});

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.

在箭头函数之前，每个新函数都定义了它自己的这个值（在构造函数的情况下是一个新对象，在严格模式函数调用中是未定义的，如果函数被称为“对象方法”则是基础对象，等等）。事实证明，面向对象的编程风格并不理想。