Angular 4 指令快速入门教程

ng new PROJECT-NAME

cd PROJECT-NAME
ng serve

import { Directive, HostBinding} from '@angular/core';

@Directive({
  selector: '[greet]'
})
export class GreetDirective {
 @HostBinding() innerText = 'Hello, Everyone!';
}
指令的应用
import { Component } from '@angular/core';

@Component({
 selector: 'app-root',
 template: `
  <h2>Hello, Angular</h2>
  <h2 greet>Hello, Angular</h2>
 `,
})
export class AppComponent { }

import { Directive, HostBinding, Input } from '@angular/core';

@Directive({
  selector: '[greet]'
})
export class GreetDirective {
  @Input() greet: string;
  @HostBinding() get innerText() {
    return this.greet;
  }
}

import { Component } from '@angular/core';

@Component({
 selector: 'app-root',
 template: `
  <h2>Hello, Angular</h2>
  <h2 [greet]="'Hello, Semlinker!'">Hello, Angular</h2>
 `,
})
export class AppComponent { }

import { Directive, HostBinding, HostListener, Input } from '@angular/core';

@Directive({
  selector: '[greet]'
})
export class GreetDirective {
  @Input() greet: string;

  @HostBinding() get innerText() {
   return this.greet;
  }

  @HostListener('click',['$event']) 
  onClick(event) {
   this.greet = 'Clicked!';
  }
}

import { Component } from '@angular/core';

@Component({
 selector: 'app-root',
 template: `
  <h2>Hello, Angular</h2>
  <h2 [greet]="'Hello, Semlinker!'">Hello, Angular</h2>
 `,
})
export class AppComponent { }

import { Directive, HostBinding, HostListener, Input, Attribute } from '@angular/core';

@Directive({
  selector: '[greet]'
})
export class GreetDirective {
  @Input() greet: string;

  @HostBinding() get innerText() {
    return this.greet;
  }

  @HostListener('click',['$event']) 
  onClick(event) {
    this.greet = 'Clicked!';
    console.dir(event);
  }

  constructor(@Attribute('author') public author: string) {
    console.log(author);
  }
}

import { Component } from '@angular/core';

@Component({
 selector: 'app-root',
 template: `
  <h2>Hello, Angular</h2>
  <h2 [greet]="'Hello, Semlinker!'" 
   author="semlinker">Hello, Angular</h2>
 `,
})
export class AppComponent { }

import { Component, TemplateRef, ViewContainerRef, ViewChild, 
 AfterViewInit } from '@angular/core';

@Component({
 selector: 'app-root',
 template: `
  <ng-template #tpl>
   Hello, Semlinker!
  </ng-template>
 `,
})
export class AppComponent implements AfterViewInit{
 @ViewChild('tpl')
 tplRef: TemplateRef<any>;

 constructor(private vcRef: ViewContainerRef) {}

 ngAfterViewInit() {
  this.vcRef.createEmbeddedView(this.tplRef);
 }
}

import { Component } from '@angular/core';

@Component({
 selector: 'app-root',
 template: `
  <ng-template #stpl>
   Hello, Semlinker!
  </ng-template>
  <ng-template #atpl>
   Hello, Angular!
  </ng-template>
  <div [ngTemplateOutlet]="atpl"></div>
  <div [ngTemplateOutlet]="stpl"></div>
 `,
})
export class AppComponent { }

import { Component } from '@angular/core';

@Component({
 selector: 'app-root',
 template: `
  <ng-template #stpl let-message="message">
   <p>{{message}}</p>
  </ng-template>
  <ng-template #atpl let-msg="message">
   <p>{{msg}}</p>
  </ng-template>
  <ng-template #otpl let-msg>
   <p>{{msg}}</p>
  </ng-template>
  <div [ngTemplateOutlet]="atpl"
   [ngOutletContext]="context">
  </div>
  <div [ngTemplateOutlet]="stpl"
   [ngOutletContext]="context">
  </div>
  <div [ngTemplateOutlet]="otpl"
   [ngOutletContext]="context">
  </div>
 `,
})
export class AppComponent {
 context = { message: 'Hello ngOutletContext!', 
  $implicit: 'Hello, Semlinker!' };
}

import { Directive, Input, TemplateRef, ViewContainerRef } from '@angular/core';

@Directive({
  selector: '[exeUnless]'
})
export class UnlessDirective {

  @Input('exeUnless')
  set condition(newCondition: boolean) {
    if (!newCondition) { 
      this.viewContainer.createEmbeddedView(this.templateRef);
    } else {
      this.viewContainer.clear();
    }
  }

  constructor(private templateRef: TemplateRef<any>,
    private viewContainer: ViewContainerRef) {
  }
}

import { Component } from '@angular/core';

@Component({
 selector: 'app-root',
 template: `
  <h2 *exeUnless="condition">Hello, Semlinker!</h2> 
 `,
})
export class AppComponent {
 condition: boolean = false;
}