我有一个存储在服务器中的api列表:ServerGetData,如下所示:
apis = {
"Repo Assignment": "https://apis.repoAssignment",
"Status Summary": "https://apis.statsSummary",
...
}
我创建了一个子组件下拉菜单:TitleDropdownComponent子组件,它显示所有api Headers :“Repo Assignment”...在我的父组件中,我想根据从子组件中选择的 Headers 呈现不同的数据表 .
现在,我可以成功从子组件中获取 Headers 并在父组件的控制台中打印它们 . 但是,在我的ngOnInit()中,相同的变量无法相应地更改,因为 Headers 变量不会改变,所以总是得到相同的api数据 . 如何在ngOnInit中更改 Headers 变量或使用ngOnChanges等其他方式?请参阅下面的我的父应用组件 . 提前致谢!
import { Component, Input, EventEmitter, Output, ViewChild, OnInit } from '@angular/core';
import { ServerGetData } from './server.getData';
import { TitleDropdownComponent } from './TitleDropdown/titleDropdown.component'
@Component({
selector: 'app-root',
templateUrl: './app.component.html',
styleUrls: ['./app.component.css'],
})
export class AppComponent implements OnInit {
// make ajax call from ServerGetData
constructor(private dataService: ServerGetData) {}
data = {};
// get Child component variables
@ViewChild(TitleDropdownComponent)
private titleComponent: TitleDropdownComponent;
onSelected(selected: string) {
// default child component title is "Repo Assignment", in here overwrite
// titleComponent.title to be selected title
this.titleComponent.title = selected;
// each time can the selected title can be printed in console
console.log(this.titleComponent.title);
return this.titleComponent.title;
}
ngOnInit(): void {
// *** No idea why in here this.titleComponent.title is not able to change accordingly and always is default title: "Repo Assignment" ***
this.dataService.getData(this.titleComponent.title).subscribe(
(data) => {
this.data = data.items;
}
);
};
}
1 回答
ngOnInit
仅在组件初始化时始终执行一次 . 它不会在以后重新执行,因为其他选择 .如果每次选择新项时都需要重新获取数据,请将代码移到onSelected方法中 .