angular - 一个组件的调用方法 Angular 2/4

Question

我试图在另一个组件中使用一个组件的方法，但出现类似 No provider for xxComponent 的错误。我该怎么做？

import { FoldersService } from '../../_services/folders.service';
import { Component, OnInit, ViewChild } from '@angular/core';

@Component({
  selector: 'app-folder-create',
  templateUrl: './folder-create.component.html',
})
export class FolderCreateComponent implements OnInit {
   constructor(
    private http: Http,
    private folderService: FoldersService,
  ) { }

  ngOnInit() { }

  saveFolder() {

  }
}

-- Class FolderEditComponent 
   import { FolderCreateComponent } from '../folder-create/folder-create.component';
@Component({
  selector: 'app-folder-edit',
  templateUrl: './folder-edit.component.html',
  styleUrls: ['./folder-edit.component.css'],
})
export class FolderEditComponent implements OnInit {
   constructor(
    private http: Http,
    private folderService: FoldersService,
    private folderCreate: FolderCreateComponent
  ) { }

  ngOnInit() { }

  // How can I do here for calling method saveFolder() of the component FolderCreateComponent

  // I try this :
  folderCreate.saveFolder(); // But I got error : ERROR Error: Uncaught (in promise): Error: No provider for FolderCreateComponent!

}

如何在组件 FolderEditComponent 中调用组件 FolderCreateComponent 的 saveFolder() 方法？

Answer 1

情况 1 - 当你想访问子组件的方法时，然后在父组件中 -

@ViewChild(ChildComponent) childComponent: ChildComponent;

childComponent.methodName();

情况 2 - 当你想从子访问父方法时 -

构造函数(@Inject(forwardRef(() => ParentComponent)) private _parent: ParentComponent){}

只需使用this._parent.methodName()