在父组件中使用click事件切换子组件中的Class

Question

我试图使用单击事件切换类的打开/关闭，我遇到的问题是我的单击事件在父组件中，而类在子组件中。我能够使用@Input()装饰器初始化类的子类，但我无法切换类之后

import { Component, AfterViewInit, Input, OnInit } from '@angular/core';
import { SidebarComponent } from './components/sidebar/sidebar.component';
@Component({
   moduleId: module.id,
   selector: 'body',
   host: {
      '[class.navMdClass]' : 'navMdClass',
      '[class]' : 'classNames'
   },
   templateUrl:'app.component.html' ,
   directives:[SidebarComponent],    
})
export class AppComponent implements OnInit {
   private isClassVisible:boolean;
   constructor () {    
   }
   ngOnInit() {
      this.isClassVisible=true;
   }
   toggleClass() {
      this.isClassVisible = !this.isClassVisible;       
   }
}
//Child component
import { Component, Input, EventEmitter, OnInit,SimpleChange } from '@angular/core';
@Component({
    moduleId: module.id,
    selector: 'sidebar',
    templateUrl:'sidebar.component.html' 
})
export class SidebarComponent implements OnInit{
    @Input() isClassVisible:boolean;
ngOnInit() { }
}
//Parent click event triggers toggleClass
<div class="nav toggle">
          <a (click)="toggleClass();" href="#" id="menu_toggle"><i class="fa fa-bars"></i></a>
      </div>
//Child div where target class is
<div class="left_col" [class.scroll-view]="[isClassVisible]" >

Answer 1

你需要去掉[class]中的大括号。scroll-view]="[isClassVisible]" to

[class.scroll-view]="isClassVisible"

Answer 2

我找到了这个问题的解决方案，这个解决方案包括将类名作为属性传递给子组件。如果你有多个类要传递到不同的位置，你可以传递一个数组属性并在适当的区域输出。

//parent component
import { Component, AfterViewInit, Input, OnInit } from '@angular/core';
import { SidebarComponent } from './components/sidebar/sidebar.component';
@Component({
   moduleId: module.id,
   selector: 'body',
   host: {
      '[class.navMdClass]' : 'navMdClass',
      '[class]' : 'classNames[0]'
   },
   templateUrl:'app.component.html' ,
   directives:[SidebarComponent]

})
export class AppComponent{
   navMdClass:boolean;
   classNames:Array<any>;
   constructor () {
      this.navMdClass=false;
      this.classNames = ['nav-md', 'scroll-view',  'sidebar-footer'];
   }
   toggleClass() {
      this.navMdClass = !this.navMdClass;
      if(this.navMdClass==false){ this.classNames[0] = 'nav-md'; this.classNames[1]="scroll-view"; this.classNames[2]="sidebar-footer"}
      if(this.navMdClass==true){  this.classNames[0] = 'nav-sm'; this.classNames[1]=""; this.classNames[2]="sidebar-footer-hide"}
      //console.log(this.classNames[0]);
   }
}
//child component
import { Component, Input, EventEmitter, OnInit, SimpleChange, OnChanges  } from '@angular/core';
@Component({
    moduleId: module.id,
    selector: 'sidebar',
    templateUrl:'sidebar.component.html',
    properties: ['cls']
})
export class SidebarComponent{
    @Input() classNames:Array<any>;
}
//Parent click event triggers toggleClass
<div class="nav toggle">
          <a (click)="toggleClass();" href="#" id="menu_toggle"><i class="fa fa-bars"></i></a>
      </div>
//Sidebar selector in parent is where you pass the cls property declared in child component and pass it the classNames array from the parent component
<sidebar [cls]="classNames"></sidebar>
//Child div where target class is
<div class="left_col {{cls[1]}}" >
<div class="{{cls[2]}}" >