具有 contentEditable div 和 ngModel 支持的 Angular 2 表单

Question

我正在尝试使用 Angular 2 Forms，但我不想使用 input，而是想使用可编辑的 div。

这个有效:

<input type="text" [(ngModel)]="value">

但这会引发错误:

<div contentEditable="true" [(ngModel)]="value"></div>

TypeError: setting a property that has only a getter

有没有办法将 div 与 Angular Forms 一起使用？我不想使用输入或文本区域

Answer 1

不是开箱即用的..

ngModel 只能在支持它的元素上访问!

您可以创建指令或自定义输入组件。

无论如何，它必须实现这个接口(interface)ControlValueAccessor。

指令:

工作演示:https://plnkr.co/edit/12vAEFf2OBS3ERu9fhwk?p=preview

import {Directive, Component, NgModule, forwardRef, ViewChild, ElementRef, HostListener, Renderer} from '@angular/core'
import {BrowserModule} from '@angular/platform-browser'
import { FormsModule, ControlValueAccessor, NG_VALUE_ACCESSOR } from '@angular/forms';

@Directive({
  selector: 'div[contentEditable]',
  providers: [
    {
      provide: NG_VALUE_ACCESSOR,
      useExisting: forwardRef(() => EditableDivDirective),
      multi: true
    }
  ]
})
export class EditableDivDirective implements ControlValueAccessor {

  constructor(private _elRef: ElementRef, private _renderer: Renderer) { }

  onChange() {
    if (this._onChange) {
      this._onChange(this._elRef.nativeElement.innerText);
    }
  }

  @HostListener('keyup', ['$event'])
  keyup(event: any) {
    this.onChange();
  }


  // ControlValueAccessor implementation
  // ====================================

  private _onChange = (_) => { }; // call it if your value changed..
  private _onTouched = () => { }; // call it "on blur" ..

  // will be called if a values comes in via ngModule !
  writeValue(val: any) {
    if (!val) val = '';

    this._renderer.setElementProperty(this._elRef.nativeElement, 'innerText', val);
  }

  registerOnChange(fn: (_: any) => void): void { this._onChange = fn; }
  registerOnTouched(fn: () => void): void { this._onTouched = fn; }
}

@Component({
  selector: 'my-app',
  template: `
    <div>
      <h2>Hello {{name}}</h2>
      <div contentEditable="true" [(ngModel)]="name">test test test</div>
    </div>
  `,
})
export class App {
  name:string;
  constructor() {
    this.name = 'Angular2'
  }
}

@NgModule({
  imports: [ BrowserModule, FormsModule ],
  declarations: [ App, EditableDivDirective ],
  bootstrap: [ App ]
})
export class AppModule {}

组件:

查看工作演示:https://plnkr.co/edit/XMSTrWSe3gN9iwVTBukz?p=preview

import {Component, NgModule, forwardRef, ViewChild, ElementRef} from '@angular/core'
import {BrowserModule} from '@angular/platform-browser'
import { FormsModule, ControlValueAccessor, NG_VALUE_ACCESSOR } from '@angular/forms';

@Component({
  selector: 'my-name-input',
  template: `
    <div>
      <label>first name</label>
      <div #firstName contentEditable="true" (keyup)="onChange()">{{this._firstName}}</div>
      <br />
      <label>last name</label><input [(ngModel)]="_lastName"  (ngModelChange)="onChange()" />
    </div>
  `,
  providers: [ // IMPORTANT !!
    {
      provide: NG_VALUE_ACCESSOR,
      useExisting: forwardRef(() => MyCompleteNameInputComponent),
      multi: true
    }
  ]
})
export class MyCompleteNameInputComponent implements ControlValueAccessor {

  @ViewChild('firstName') editableDiv: ElementRef;

  private _firstName: string = '';
  private _lastName: string = '';

  onChange() {

    this._firstName = this.editableDiv.nativeElement.innerText;

    if (this._onChange) {
      this._onChange(this._firstName + ' ' + this._lastName);
    }
  }


  // ControlValueAccessor implementation
  // ====================================

  private _onChange = (_) => { }; // call it if your value changed..
  private _onTouched = () => { }; // call it "on blur" ..

  // will be called if a values comes in via ngModule !
  writeValue(val: any) {
    if (!val || !val.split) val = '';

    let splitted = val.split(' ');
    this._firstName = splitted[0] || '';
    this._lastName = splitted[1] || '';
  }

  registerOnChange(fn: (_: any) => void): void { this._onChange = fn; }
  registerOnTouched(fn: () => void): void { this._onTouched = fn; }
}

@Component({
  selector: 'my-app',
  template: `
    <div>
      <h2>Hello {{name}}</h2>
      <my-name-input [(ngModel)]="name"></my-name-input>
    </div>
  `,
})
export class App {
  name:string;
  constructor() {
    this.name = 'Angular2'
  }
}

@NgModule({
  imports: [ BrowserModule, FormsModule ],
  declarations: [ App, MyCompleteNameInputComponent ],
  bootstrap: [ App ]
})
export class AppModule {}