Javascript Angular 2+,在下拉列表中更改读取值并加载数据-json文件
需要任何版本2,3,4,5的帮助,我从过去两周开始尝试。任何帮助都将不胜感激 抱歉,由于代码太大,我无法将其添加到Plunker或JSFIDLE中 我的工作流程是这样的 1-加载metadata.json 2-从metadata.json中读取第一个值 3-从APP_初始化器中的文件夹加载第一个json 4-在下拉列表中填充metadata.json中的所有值 5-每当下拉值更改时,加载relaevant json并在UI中显示对象 我有3个组件 Navigation.component下拉列表更改正在此处触发 dashboard.component数据将根据下拉列表内容进行更改 programmer.component数据将根据下拉列表内容进行更改 每当触发下拉更改事件时,我都希望从json加载数据 metadata.json app.config.tsJavascript Angular 2+,在下拉列表中更改读取值并加载数据-json文件,javascript,json,angular,Javascript,Json,Angular,需要任何版本2,3,4,5的帮助,我从过去两周开始尝试。任何帮助都将不胜感激 抱歉,由于代码太大,我无法将其添加到Plunker或JSFIDLE中 我的工作流程是这样的 1-加载metadata.json 2-从metadata.json中读取第一个值 3-从APP_初始化器中的文件夹加载第一个json 4-在下拉列表中填充metadata.json中的所有值 5-每当下拉值更改时,加载relaevant json并在UI中显示对象 我有3个组件 Navigation.component下拉列表
import { Injectable } from '@angular/core';
import { Http } from "@angular/http";
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/catch';
import { Observable } from 'rxjs/Observable';
@Injectable()
export class AppConfig {
config: any;
user: any;
objects: any;
fileName: any;
constructor(private http: Http) {
console.log('ConfigService called.')
}
load(projectName) {
return new Promise((resolve) => {
/** This method: Loads "host_configuration.json" to get the current working environment. */
this.http.get('./assets/host_configuration.json').map(res => res.json())
.subscribe(config => {
console.log('Configuration loaded');
this.config = config;
/** This method: Loads all the objects from json */
let getSummaryParameters: any = null;
getSummaryParameters = this.http.get('./assets/json/' + projectName);
if (getSummaryParameters) {
getSummaryParameters
.map(res => res.json())
.subscribe((response) => {
this.objects = response;
return resolve(true);
});
} else {
return resolve(true);
}
});
});
}
loadMetadata() {
return new Promise((resolve) => {
//reading metadata.json
this.http.get('./assets/metadata.json').map(res => res.json())
.subscribe(fileName => {
console.log('metadata loaded');
this.fileName = fileName;
return resolve(true);
});
});
}
}
app.module.ts
dashboard.component.ts
程序员.component.ts
navigation.component.ts
由于您无法共享演示,我制作了自己的演示,演示如何从API/本地json加载数据,您可以在这里尝试 请随意询问这是否不是您想要的场景/我理解错了 这里做了两件事,首先,从构造函数中获取元数据,它将在初始化应用程序时加载您的数据,然后在选项中选择一个单击方法以获取所选数据,然后该数据可以发送到url以获取另一个数据 我不知道我在这里使用的是哪个css框架AngularMaterial2 app.component.html app-config.class.ts
谢谢你的回答。我只想知道几件事。1.我的下拉菜单和仪表板位于不同的组件中。我想从navigation.component到dashboard.component获取{{meta}}值。2.初始加载我需要加载值,而不仅仅是下拉列表。你能帮我一下吗?如果我做对了,那么你需要从路由器传递值并接收值,然后打电话给一个服务,在那里你可以得到你所需要的。任何参考JSFIDLE,plunker请非常感谢你,让我检查一下。我看到一个问题,初始数据没有更新。我想在初始化中显示下拉值和帖子。这可能吗?是的,您需要一个服务来完成这项工作,或者@Input/@Output将数据从父级传递到子级,反之亦然。你可以看到我在这里使用app config作为一个服务来保存数据。
import { Injectable } from '@angular/core';
import { Http } from "@angular/http";
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/catch';
import { Observable } from 'rxjs/Observable';
@Injectable()
export class AppConfig {
config: any;
user: any;
objects: any;
fileName: any;
constructor(private http: Http) {
console.log('ConfigService called.')
}
load(projectName) {
return new Promise((resolve) => {
/** This method: Loads "host_configuration.json" to get the current working environment. */
this.http.get('./assets/host_configuration.json').map(res => res.json())
.subscribe(config => {
console.log('Configuration loaded');
this.config = config;
/** This method: Loads all the objects from json */
let getSummaryParameters: any = null;
getSummaryParameters = this.http.get('./assets/json/' + projectName);
if (getSummaryParameters) {
getSummaryParameters
.map(res => res.json())
.subscribe((response) => {
this.objects = response;
return resolve(true);
});
} else {
return resolve(true);
}
});
});
}
loadMetadata() {
return new Promise((resolve) => {
//reading metadata.json
this.http.get('./assets/metadata.json').map(res => res.json())
.subscribe(fileName => {
console.log('metadata loaded');
this.fileName = fileName;
return resolve(true);
});
});
}
}
import { BrowserModule } from '@angular/platform-browser';
import { NgModule, APP_INITIALIZER } from '@angular/core';
import { FormsModule } from '@angular/forms';
import { RouterModule } from '@angular/router';
import { HttpClientModule } from '@angular/common/http';
import { HttpModule, JsonpModule } from '@angular/http';
import { AppRoutes } from './app.routing';
import { AppConfig } from './app.config';
import { AppComponent } from './app.component';
import { NavigationComponent } from './navigation/navigation.component';
import { SharedModule } from './shared/shared.module';
import { BrowserAnimationsModule } from '@angular/platform-browser/animations';
import { BreadcrumbsComponent } from './navigation/breadcrumbs/breadcrumbs.component';
import { TitleComponent } from './navigation/title/title.component';
@NgModule({
declarations: [
AppComponent,
NavigationComponent,
BreadcrumbsComponent,
TitleComponent
],
imports: [
BrowserModule,
BrowserAnimationsModule,
RouterModule.forRoot(AppRoutes),
SharedModule,
HttpClientModule,
HttpModule,
JsonpModule,
FormsModule
],
providers: [AppConfig,
{
provide: APP_INITIALIZER,
useFactory: (config: AppConfig) => () => config.load('project_q_1234.json'),
deps: [AppConfig],
multi: true
}
],
bootstrap: [AppComponent]
})
export class AppModule { }
import { Component, OnInit } from '@angular/core';
import { Chart } from 'chart.js';
import { AppConfig } from '../../app.config';
declare var Chart;
@Component({
selector: 'app-dashboard',
templateUrl: './dashboard.component.html',
styleUrls: [
'./dashboard.component.css'
]
})
export class DashboardComponent implements OnInit {
constructor(public appConfig: AppConfig, private hostConfig: AppConfig, public getSummaryParameters: AppConfig) { }
ngOnInit() {
this.updates();
}
updates() {
//assign all Parameters to objects
this.objects = this.getSummaryParameters.objects;
var JsonData = this.objects.Information.data;
console.log(JsonData["0"]["0"] + " : " + JsonData["0"][1]);
}
}
import { Component, OnInit, ViewEncapsulation } from '@angular/core';
import { Chart } from 'chart.js';
import { CommonModule } from '@angular/common';
import { NgbModal, ModalDismissReasons } from '@ng-bootstrap/ng-bootstrap';
import { AppConfig } from '../../app.config';
declare function ChangeSortOrder(): any;
@Component({
selector: 'app-simple-page',
templateUrl: './programmer.component.html'
})
export class ProgrammerComponent implements OnInit {
objects;
constructor(public appConfig: AppConfig, private hostConfig: AppConfig, public getSummaryParameters: AppConfig, private modalService: NgbModal) { }
ngOnInit() {
this.updateData();
}
updateData() {
//assign all Parameters to objects
this.objects = this.getSummaryParameters.objects;
}
}
import { Component, ElementRef, OnInit, ViewChild, Injectable, NgModule } from '@angular/core';
import { Router, ActivatedRoute } from '@angular/router';
import { Http } from "@angular/http";
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/catch';
import { AppConfig } from '../app.config';
import { DashboardComponent } from '.././pages/dashboard/dashboard.component';
import { ProgrammerComponent } from '.././pages/programmer/programmer.component';
@Component({
selector: 'app-admin',
templateUrl: './navigation.component.html',
providers: [DashboardComponent, ProgrammerComponent]
})
@Injectable()
export class NavigationComponent implements OnInit {
fileName: any;
selectedfileName: any;
config: any;
objects: any;
constructor(public menuItems: MenuItems, private http: Http, private appConfig: AppConfig, public router: Router,
private hostConfig: AppConfig, public getSummaryParameters: AppConfig, private dashboardComponent: DashboardComponent,
private programmerComponent: ProgrammerComponent) {
}
ngOnInit() {
this.appConfig.loadMetadata().then(fileName => {
this.fileName = this.appConfig.fileName;
//Initial loading for project Drop-down, Fetch first JSON from metadata.json
this.selectedfileName = 'project_q_1234.json';
});
}
refreshApp(projectName) {
this.appConfig.load(projectName).then(objects => {
this.objects = objects;
this.updateData();
//this commented code partially works but data is not loading properlly
//this.dashboardComponent.updates();
//this.programmerComponent.updateData();
//this.qCProgrammerComponent.updateQCData();
});
}
updateData() {
console.log("Dropdown change start");
//load all the host related settings
this.config = this.hostConfig.config;
localStorage.setItem('url', this.config.host);
localStorage.setItem('folder', this.config.folder);
}
<p>
Using jsonplaceholder.typicode.com API
</p>
<mat-form-field style="width: 100%">
<mat-select placeholder="Select Any Users" [(value)]="selectedUser">
<mat-option *ngFor="let meta of metadata" (click)="getInfoAboutIndividualMeta(meta)" [value]="meta.name">
{{ meta.name }}
</mat-option>
</mat-select>
</mat-form-field>
<mat-form-field style="width: 100%" *ngIf="selectedUser">
<mat-select placeholder="Select Posts from {{selectedUser}}">
<mat-option *ngFor="let post of posts" (click)="selectedPost(post)" [value]="post.title">
{{ post.title }}
</mat-option>
</mat-select>
</mat-form-field>
<mat-card *ngIf="selectPost">
<h1>{{selectPost?.title}}</h1>
<p [innerHTML]="selectPost?.body"></p>
</mat-card>
name = 'Angular 6';
metadata: any[];
posts: any[];
selectedUser: string;
selectPost: Object;
constructor(private appConfig: AppConfig) {
this.metadata = [];
this.posts = [];
this.initialize();
}
initialize() {
this.appConfig.getMetadataJSON().subscribe(res => {
this.metadata = res;
this.selectedUser = this.metadata[0].name;
});
}
getInfoAboutIndividualMeta(meta: Object) {
console.log(meta);
const userId = meta.id;
this.appConfig.getIndividualMetadataJSON(userId).subscribe( res => {
this.posts = res;
});
}
selectedPost(post: Object) {
this.selectPost = post;
}
import { Injectable } from '@angular/core';
import { HttpClient } from "@angular/common/http";
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/catch';
import { Observable } from 'rxjs';
@Injectable()
export class AppConfig {
constructor(private httpClient: HttpClient) {
}
public getMetadataJSON(): Observable<any> {
// Due to stackblitz can't get the local access I put this value to another api source
// const apiUrl = './assets/metadata.json'; // You can use this as well
const apiUrl = 'https://jsonplaceholder.typicode.com/users';
return this.httpClient.get(apiUrl);
}
public getIndividualMetadataJSON(userId: number): Observable<any> {
const apiUrl = 'https://jsonplaceholder.typicode.com/posts?userId=' + userId;
return this.httpClient.get(apiUrl);
}
}