Javascript 类型有单独的私有属性声明
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Types have separate declarations of a private property
提问by Mike Me
I am learning Angular (which is written in TypeScript) and I stumbled upon this error:
我正在学习 Angular（用 TypeScript 编写）并且偶然发现了这个错误：
Class 'SnackbarService' incorrectly extends base class 'MatSnackBar'. Types have separate declarations of a private property '_overlay'.
“SnackbarService”类错误地扩展了基类“MatSnackBar”。类型具有私有属性“_overlay”的单独声明。
when trying to extend MatSnackBarfrom @angular/material.
当试图MatSnackBar从@angular/material.
This is my code:
这是我的代码：
import { MatSnackBar } from '@angular/material';
import { Overlay } from '@angular/cdk/overlay';
import { LiveAnnouncer } from '@angular/cdk/a11y';
...
export class SnackbarService extends MatSnackBar {
constructor(
private _overlay: Overlay,
private _liveAnnouncer: LiveAnnouncer,
...
) {
super(_overlay, _liveAnnouncer, ...);
}
}
}
Any help with any type of explanation on why this happens would be really be appreciated.
任何类型的解释为什么会发生这种情况的任何帮助将不胜感激。
回答by Suren Srapyan
This happens because by declaring the constructor as taking a private _overlayparameter, you have created your own _overlay, but that is already defined in the base class MatSnackBar.
发生这种情况是因为通过将构造函数声明为接受private _overlay参数，您已经创建了自己的_overlay，但它已经在基类中定义MatSnackBar。
Remove the privatepart from the declaration and inherit it from the base class. Do the same for the other constructor parameters.
private从声明中删除该部分并从基类继承它。对其他构造函数参数执行相同操作。
export class SnackbarService extends MatSnackBar{
constructor(
_overlay: Overlay,
_liveAnnouncer: LiveAnnouncer,
...
) {
super(_overlay, _liveAnnouncer, ...);
}
}
}
You can still access them via this.
您仍然可以通过以下方式访问它们 this.
