问题描述
我的代码如下
@Component({
selector: 'my-app',
template: `
<ul>
<li *ngFor = 'let hero1 of heros2'>
{{hero1.name}}
</li>
</ul>
`})
export class AppComponent {
heros2 : any = [
new heross('lee', 'lee'),
new heross('lee1', 'lee1'),
];}
class heross{
private name : string;
constructor(name : string, details : string){
this.name = name;
}}
bootstrap(AppComponent);
为什么我可以在视图中访问名称并显示名称,前提是我给了它私有关键字
why am I able to access name in the view and displaying name, provided that I have given it private keyword
推荐答案
如果您尝试:
class A {
private x: number;
}
let a = new A();
console.log(a.x);
(操场上的代码)
你会得到一个编译错误:
You'll get a compilation error:
属性x"是私有的,只能在A"类中访问
我怀疑(因为我不是 Angular 开发人员),你没有得到它的原因是你在一个字符串中有 hero1.name
所以打字稿编译器没有t 将 hero1
视为变量.
The reason you're not getting that, I suspect (as I'm not an angular developer), is that you're having hero1.name
in a string so the typescript compiler doesn't treat hero1
as a variable.
我敢打赌,如果您尝试:
I bet that if you try:
let obj = new heross("name", "details");
console.log(`heross.name: ${ obj.name }`);
然后你会得到编译错误.
区别在于 ${}
而不是 {{}}
.
Then you'll get the compilation error.
The difference being ${}
instead of {{}}
.
但是,如果您问为什么可以在运行时访问它,那是因为 javascript 中没有可见性的概念,它不会通过编译器.
If however you're asking why that's accessible at runtime, then that's because there's no notion of visibility in javascript, it doesn't get pass the compiler.
角度双花括号 ({{ }}
):
双花括号符号 {{ }} 将表达式绑定到元素是内置的 Angular 标记
你不需要打勾,你可以使用普通的单/双引号.
Which you don't need to put into ticks, you can just use regular single/double quotes.
以及 javascript 模板文字(${ }
):
模板文字是允许嵌入表达式的字符串文字.您可以使用多行字符串和字符串插值功能他们.在之前的版本中,它们被称为模板字符串"ES2015/ES6 规范
更简单:
let x = 4;
console.log(`x={{ x }}`); // outputs 'x={{ x }}'
console.log(`x=${ x }`); // outputs 'x=4'
这篇关于为什么我可以访问类的私有成员?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!