我是MEAN堆栈的新手,无法在UI中刷新数据更改。我知道数据已经正确地保存在MongoDB中,并且也可以进行检索,因为当我创建待办事项并刷新页面时,新添加的待办事项会出现在待办事项列表中。问题在于它不是动态发生的。
我已经尝试了许多不同的方法,包括NgZone和ChangeDetectorRef来检测更改,但不确定我做错了什么。.
让我知道是否需要更多信息。.谢谢!
“待办事项列表”组件:
import { Component, Input, OnInit, NgZone } from '@angular/core';
import { Todo } from '../todo.model';
import { TodoService } from '../../todo.service';
@Component({
selector: 'app-todo-list',
templateUrl: './todo-list.component.html',
styleUrls: ['./todo-list.component.scss'],
providers: [TodoService]
})
export class TodoListComponent implements OnInit {
@Input() todos: Todo[] = [];
constructor(private _todoService: TodoService, private zone: NgZone){}
getTodos() {
console.log('todo list - get todos');
this._todoService.getTodos()
.subscribe(resTodoData => {
this.zone.run(() => {
this.todos = resTodoData;
});
});
}
ngOnInit() {
console.log('todo list - init');
this.getTodos();
}
}
服务组件:
import { Injectable, NgZone } from '@angular/core';
import { Http, Response, Headers, RequestOptions } from
'@angular/http';
import { map } from 'rxjs/operators';
import { Todo } from './todos/todo.model';
@Injectable({
providedIn: 'root'
})
export class TodoService {
// these were configured in express server
private _getUrl = "/api/todos";
private _postUrl = "/api/todo";
constructor(private _http: Http, private zone: NgZone) { }
getTodos() {
let json = this._http.get(this._getUrl)
.pipe(map((response: Response) => response.json()));
return json;
}
addTodo(todo: Todo) {
let headers = new Headers({ 'Content-Type': 'application/json'
});
let options = new RequestOptions({ headers: headers });
return this._http.post(this._postUrl, JSON.stringify(todo),
options)
.pipe(map((response: Response) => response.json()));
}
}