javascript - 如何正确地将功能从 component.ts 移动到服务文件？

Question

我在我的 component.ts 中编写了一个发送 PUT 请求的函数。它可以正常工作，但我想将该功能移至 service.ts 文件。我移动了它，但它不起作用。当我单击“保存”时，它在控制台中显示错误：

FormsComponent.html:32 错误类型错误：_co.editForm 不是 Object.eval 的函数 [as handleEvent] (FormsComponent.html:32) at handleEvent (core.js:23008) at callWithDebugContext (core.js:24078) at Object .debugHandleEvent [as handleEvent] (core.js:23805) at dispatchEvent (core.js:20457) at core.js:20904 at HTMLButtonElement。(platform-b​​rowser.js:993) 在 ZoneDelegate.push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invokeTask (zone.js:423) 在 Object.onInvokeTask (core.js:17279) 在ZoneDelegate.push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invokeTask (zone.js:422) [e-mail]:32 [e-mail]:18234 push../node_modules/@angular /core/fesm5/[e-mail]:24040 推..

这是我的 forms.component.ts 文件：

import { Component, OnInit, OnDestroy } from '@angular/core';
import { ActivatedRoute, Router } from '@angular/router';
import { FormService } from './forms.service';
import { form } from './form-interface';
import { HttpClient } from '@angular/common/http';

@Component({
  selector: 'app-forms',
  templateUrl: './forms.component.html',
  styleUrls: ['./forms.component.css']
})


export class FormsComponent implements OnInit {

  formsUrl = "https://jsonplaceholder.typicode.com/posts";
  id: any;
  form: form = {
    id: 0,
    userId: 0,
    title: '',
    body: ''
  };

  constructor(private formService: FormService ,private route: ActivatedRoute,
    private router: Router, private http: HttpClient) { }

  ngOnInit() {
    this.id=this.route.snapshot.params['id'];

    this.formService.getForms(this.id).subscribe(
      (forms: any) => {
        this.form = forms[0];
        console.log(this.form);
      }
    );

  }

  deleteForm() {
    this.http.delete(this.formsUrl + "/" + this.form.id)
    .subscribe(
      data  => {
      console.log("DELETE Request is successful ", data);
      },
      error  => {
      console.log("Error", error);
      }
    );
  }

}

这是我的 forms.service.ts 文件：

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { form } from './form-interface';



@Injectable({
    providedIn: 'root'
}) 

export class FormService {

formsUrl = "https://jsonplaceholder.typicode.com/posts";
form: form = {
    id: 0,
    userId: 0,
    title: '',
    body: ''
  };


    constructor(private http: HttpClient) { }

    getForms(id) {
        return this.http.get('https://jsonplaceholder.typicode.com/posts'
        + "?id=" + id)
      }

      editForm() {
        fetch(this.formsUrl + "/" + this.form.id, {
          method: 'PUT',
          body: JSON.stringify(this.form),
          headers: {
            "Content-type": "application/json; charset=UTF-8"
          }
        })
        .then(response => response.json())
        .then(json => console.log(json));
      }


}

这是我的 HTML 文件：

<div class="forms container">
  <form #postForm="ngForm">
      <div class="form-group">
          <label for="title">Title</label>
          <input [(ngModel)]="form.title"
          name="title"  
          id="title" 
          type="text" 
          class="form-control"
          >
      </div>
      <div class="form-group">
        <label for="body">Body</label>
        <textarea [(ngModel)]="form.body" 
        name= "body" 
        id="body" 
        cols="30" 
        rows="10" 
        class="form-control"
        ></textarea>
      </div>
      <button class="btn btn-success" (click) = editForm()>Save</button>
      <button class="btn btn-danger pull-right" (click) = deleteForm()>Delete</button>
  </form>
</div>

标签： javascriptangulartypescript

Answer 1

您不能调用editForm()模板，因为它在您的组件中不存在。如果您想从服务中调用该函数，请formService.editForm()改用

但在这种情况下，您需要formService公开，所以使用public formService: FormService而不是private formService: FormService.

您还可以在组件中克隆该功能，因此您无需更改模板并将服务公开，如public editForm = formService.editForm

或者

editForm() {
     return this.formService.editForm();
}